Answer:
it will be 8ms-1
Explanation:
MaUa+MbUb=MaVa+MbVb
A hammer is used to hit a nail into a board. Which statement is correct about the forces at play between the nail and the hammer? The nail exerts an equal force on the hammer in the same direction. The nail exerts a much smaller force on the hammer in the opposite direction. The nail exerts an equal force on the hammer in the opposite direction. The nail exerts a much smaller force on the hammer in the same direction.
Answer:
The nail exerts an equal force on the hammer in the opposite direction.
Explanation:
The Newtons third law states that there is an equal an opposite reaction for every action. When hammer pushes the nail, the nail will push the hammer back in opposite direction. When the hammer hits a nail then nail will exert the equal and opposite force to the hammer. These both objects will exert force on each other in opposite directions.
Hello, I am BrotherEye
Answer:
Answers are
1. "The nail exerts an equal force on the hammer in the opposite direction."
2. "500 N"
3. "The iron piece exerts a force of 1 N on the magnet in the opposite direction."
4. "When mass moves closer to the point of rotation, rotational inertia decreases."
5. "The skater spins slower because his rotational inertia has increased."
Explanation:
A block is attached to the end of a spring. The block is then displaced from its equilibrium position and released. Subsequently, the block moves back and forth on a frictionless surface without any losses due to friction. Which one of the following statements concerning the total mechanical energy of the block-spring system this situation is true?
1. The total mechanical energy is dependent on the maximum displacement during the motion.
2. The total mechanical energy is at its maximum when the block is at its equilibrium position
3. The total mechanical energy is constant as the block moves back and forth.
4. The total mechanical energy is only dependent on the spring constant and the mass of the block.
Answer:
The correct option is;
3. The total mechanical energy is constant as the block moves back and forth
Explanation:
The total mechanical energy is the sum of the potential and kinetic energies of the system
For a system that is isolated from the effects of external forces, but being acted upon by the internal conservative forces within the system, the total mechanical energy is constant
For a black and spring system, we have total mechanical energy, E = 1/2×K×A².
Where;
K = Constant
A = The amplitude of motion
Therefore, where there is no loss to friction, with A, remaining constant, the total mechanical energy will be constant.
SHOW ADEQUATE WORKINGS IN THIS SECTION
12. Wale and Lekan of 55kg and 60kg respectively ran a race of 200m.
i. Calculate their work done in KJ
ii. If wale finished the race in 25secs while Lekan finished in 30secs, calculate their
power and who is more powerful out of these two. ( g = 10m/secs)
13. A machine has a velocity ratio of 5 and is 800
/0 efficient. If the machine is carrying a load
of 200kg, what will be effort applied?
Please help me answer anyone that you understand
Answer:
12 i. The work done by Wale = 107.910 kJ
The work done by Lekan = 117.720 kJ
Total work done = 225.36 kJ
ii. Wale's power = 4.3164 kW
Lekan's power = 3.924 kW
Wale has more power and is more powerful than Lekan
13. 313.92 N
Explanation:
i. The work done, W = Force, F × Distance moved by the force, D
The given parameters are
The mass of Wale = 55 kg
The mass of Lekan = 60 kg
The acceleration due to gravity, g =9.81 m/s²
The motion force of Wale and Lekan are;
Motion force of Wale = 9.81 × 55 = 539.55 N
Motion force of Lekan = 9.81 × 60 = 588.6 N
The work done by Wale = 539.55 × 200 = 107910 J = 107.910 kJ
The work done by Lekan= 588.6 × 200 = 117720 J = 117.720 kJ
107910 + 117720 =225630 J = 225.36 kJ
ii. Power = Work done/time
Wale finished the race in 25 s, therefore, his power = 107910/25 = 4316.4 W
Lekan finished the race in 30 s, therefore, his power = 117720/30 = 3924 W
Wale has more power and is more powerful than Lekan
13. The velocity ratio = 5
V. R. = Distance moved by effort/(Distance moved by load)
Efficiency = 80%
Work done by effort = x
Work done by machine = Efficiency × Work done by effort = 0.8 × x
Distance moved by effort, E = V. R. × Distance moved by load, D = 5 × D
Work done by effort = Force × Distance moved = 200×9.81× E
Work done by effort = 1962×E = 1962×E = 1962×5×D
Work done by machine = 1962 × D, when D = 1, we have;
0.8 × 1962×1 = 1569.6 J
Work done by effort = Force × Distance moved
Work done by effort = Force × 5×D = Force × 5 (D = 1)
From the principle of conservation of energy, we have;
Energy is neither created nor destroyed
Therefore
Work done by effort = Force × 5 = 1569.6 J
Force = 1569.6 /5 = 313.92 N.
What is the density of a 15 kg block of wood with a volume of 1.5 cubic meters;
d=m/v?
A)10
B)150
C)20
Answer: A) 10
Explanation:
I plugged in the numbers into a calculator.
Ex:
The formula for density is d=m/v so I divided 15 by 1.5 and it gave me 10.
Compare diffusion of chlorine gas into air and into vaccuum. Explain your answer
Answer:
Diffusion depends among many other things also upon the concentration gradient of the diffusing substance.For example if there are two boxes with given particles first isolated from each other and if they are bought in contact, then there is a net diffusion of particles from a box with higher concentration of particles to box with lower concentration. And also diffusion rate depends at any instant directly on the concentration difference between them at that instant.Now the vaccum is equivalent to an empty box which means with this one leads to a maximum diffusion rate when bought in contact with a box with particles because there is maximum concentration difference.That is vaccum is empty ( except for energy perturbations and a small concentration of particles which will be zero for our purpose) and any bunch of particles will find least resistance to diffuse as just outside this bunch there is ‘0' concentration of the particles.
PLS HELP ME Define Derived Quantities ?
Derived Quantities
Explanation: Those physical quantities which are derived from fundamental quantities are called derived quantities and their units are called derived units. e.g., velocity, acceleration, force, work etc.
Answer:
These are quantities calculated from two or more measurements
Explanation:
They can't me measured directly.
They can only be computed.
They are calculated in PHYSICAL SCIENCE.
hope it helps.
A car is moving on straight highway with a speed of 108 km/h.
Answer:
5.3333 sec
Explanation:
initial speed: u = 108km/hr or 30 m/s
final speed: v = 0m/s
distance travelled: s = 80m
time the car took to stop: = t sec
[tex]v^{2} - u^{2}[/tex] = 2as,
a = ([tex]v^{2} - u^{2}[/tex])/2s
a = (0-900)/160
a = -5.625 [tex]ms^{-2}[/tex]
v = u + at,
t = (v - u)/a
t= (0 - 30)/(-5.625)
t = 5.3333 sec
64. A heart pacemaker fires 72 times a minute, each time a 25.0-nF capacitor is charged (by a battery in series with a resistor) to 0.632 of its full voltage. What is the value of the resistance
Answer:
=33 .3×10^6Ω
=33.3M Ω
Explanation:
We were told to calculate the Resistance value,
Given the heart pacemaker fires as 72 times a minute, which is the time constant
Then we can convert the pacemaker fires of 72 times a minute to seconds for unit consistency.
1 minutes= 60secs
Then ,Time constant τ=60secs/72=0.8333 seconds
Time constant τ can be calculated using the formula below
τ= RC
Where R= resistance
C = capacitance
Then making RESISTANCE subject of formula we have
R=τ/C
But Capacitance=25.0-nF = 25×10^25F
Substitute the values we have
R=0.833/25×10^25
=33 .3×10^6 Ω
But can still be converted to M Ω= 33.3M Ω
Therefore, the resistance is 33 .3×10^6 Ω or 33.3M Ω
NOTE: 1M= 10^6
The value of the resistance will be "3.33×10⁷ Ω".
Resistance based problem:According to the question,
Capacitor, C = 25.0 nF
60 sec - 72 fires
now,
Time for 1 fire,
[tex]t = \frac{60}{72}[/tex]
[tex]= \frac{5}{6} \ sec[/tex]
Now,
⇒ [tex]V = V_0 (1-e^{-\frac{t}{RC} })[/tex]
[tex]0.632 V_0=V_0(1-e^{\frac{-\frac{5}{6} }{R.25 n C} })[/tex]
[tex]e^{-\frac{1}{R\times 30\times 10^{-9}} } = 1-0.632 = 0.368[/tex]
[tex]= 2.72[/tex]
By taking "log" both sides,
⇒ [tex]ln \ e^{\frac{1}{R\times 30\times 10^{-9}} } = ln \ 2.72[/tex]
hence,
The Resistance be:
⇒ [tex]R = \frac{10^9}{30}[/tex]
[tex]= 3.33\times 10^7 \ \Omega[/tex]
Thus the above approach is right.
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1 point
40 The diagram below shows an electrical circuit made up of a cell and three loads. The
voltage established by the cell and the resistance of each load is marked on the
diagram. Select the current flowing through the 3-ohm load.
www
1 ohm
12V
2 ohms
WWW
3 ohms
www
A. 4 amps
B. 2 amps
C. 5 amps
D. 0.25 amps
SPS106 DOK 3
Answer:
Option B. 2 A.
Explanation:
The following data were obtained from the question:
Resistance 1 (R1) = 1 Ω
Resistance 2 (R2) = 2 Ω
Resistance 3 (R3) = 3 Ω
Potential difference (V) = 12 V.
Current through the 3 Ω (I3) =?
Next, we shall determine the total resistance of the circuit.
This can be obtained as follow:
Resistance 1 (R1) = 1 Ω
Resistance 2 (R2) = 2 Ω
Resistance 3 (R3) = 3 Ω
Total resistance (R) =.?
R = R1 + R2 + R3
R = 1 + 2 + 3
R = 6 Ω
Next, we shall determine the current flowing in the circuit.
This can be obtained as follow:
From ohm's law,
Voltage (V) = current (I) x resistance (R)
V = IR
Potential difference (V) = 12 V.
Resistance (R) = 6 Ω
Current (I) =?
V = IR
12 = I x 6
Divide both side by 6
I = 12/6
I = 2 A.
Since the circuit is in series connection, therefore, the same current will flow through each resistor.
Therefore, the current through the the 3 Ω load is 2 A.
SCIENCE
1-1 FORCE
What is gravitational force?
(गुरुत्वाकर्षण बल भनेको के हो?"
Write two factors that affect gravitation, (गुरुत्वाकर्षणलाई असर
Write one effect of gravitation that is seen in the sea. (गुरुत्वा
What is gravitational constant? (गुरुत्वाकर्षण अचर भनेको हो ?
Write the value of gravitational constant? (गुरुत्वाकर्षण अचरक
What is gravity? (गुरुत्व बल के हो?)
Vrite two factors that affect ravity. (गुरुत्व बललाई असर गर्ने
-2 FORCE
What is acceleration due to gravity? (गुरुत्व प्रवेग के हो)
rite the value of g at the poles and in the equator of the
त उल
Answer:
is a force that attracts any two objects with a mass
why do objects in equilibrium have a net force of 0?
Answer:
Because there is no net force acting o an object in equilibrium.
Explanation:
When object is in equilibrium (either at rest or moving with constant velocity, the net force acting o it is zero.A vector can only have zero magnitude fall of its components are zero this means that all forces acting on the object are balanced.
A charge (uniform linear density = 8.8 nC/m) lies on a string that is stretched along an x axis from x = 0 to x = 3.1 m. Determine the magnitude of the electric field at x = 5.2 m on the x axis.
Answer:
answer= 73.1256 [tex]i[/tex]
Explanation:
The electric charge linear density is equal to 8.8 x[tex]10^{-9}[/tex]
the length of the string is 3.1m
The magnitude of the electric field at the length of the string equal to 5.2 meters can be calculated with the formula ;
- E = λ / 4πε₀ [ [tex]l[/tex] / α ( α +
Solution:
E = 8.8 x[tex]10^{-9}[/tex] / 4πε₀ [ 3.1/ 5.2( 5.2 + 3.1) ] [tex]i[/tex]
= 1018.0995 [0.07183] [tex]i[/tex]
= 73.1256 [tex]i[/tex]
Sarai strolls to the right with an average speed of 1.2m/s for 1500 seconds. What was Sarai's displacement in meters?
Answer:
1800m
Explanation:
rearrange speed= distance/time
to distance=time*speed
1.2*1500=1800
Sarai's displacement in meters will be 1800 when it strolls to the right with an average speed of 1.2m/s for 1500 seconds.
What is speed?Speed is defined as the ratio of the distance moved by the object at a particular time. The unit of speed is measured in the meter per second, miles per hour, etc.
Average velocity is defined as the sum of all the distances traveled by an object to the time taken by the object to cover the total distance.
Given that Sarai strolls to the right with an average speed of 1.2m/s for 1500 seconds.
To calculate the distance traveled by the object convert the velocity formula into the form of the distance formula then solve for the value of distance.
Velocity = Distance / time
1.2 = Distance / 1500
Distance = 1.2 x 1500= 1800 meters
Therefore, Sarai's displacement in meters will be 1800 when it strolls to the right with an average speed of 1.2m/s for 1500 seconds.
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Is the ultraviolet ray monochromatic or polychromatic?
Answ
In real world application Ultraviolet is not a color as it it can’t be seen by the human eye. It is a high frequency part of the Suns electromagnetic radiation. Even though UltraViolet sounds like a color, the Ultra in this case signifies that it is beyond Violet and thus beyond the visible part of the electromagnetic spectrum. They are not depicted with a color on spectrum charts, since we can’t see it we can’t truly classify it as a color no more than can we equate the other parts of the spectrum like XRays, Gamma Rays and Radio Waves with colors. These and other non-visible parts of the spectrum are measured instead with wavelengths. So the answer is no they would not be monochromatic, or any color at all.
Red, Orange, Yellow, Green, Blue, Indigo and Violet are the visible colors of the electromagnetic spectrum. They, combined together are called white light and our atmosphere acts like a prism to divide them into separate and apparently distinct colors. Outside the visible Red you have Infrared which is invisible to the human eye and is the heat we feel from the sun. Outside the Violet end of the visible spectrum is where UVA, UVB and UVC are found, and these are the eye and skin damaging rays. UV rays are also invisible to the human eye (but visible to certain birds of prey such as raptors
Explanation:
How much does the speed of a car increase if it accelerates
uniformly at 2.5 meters per second squared for 5 seconds?
Answer:
12.5 m/s
Explanation:
a = Δv / Δt
2.5 m/s² = Δv / 5 s
Δv = 12.5 m/s
URGENT!! Look at attached image to see question.
Explanation:
The answer is option B
The number of reactant molecules and product molecules is even.
An eletric pump in the ground floor
building taken 15 then to fill
a tank of volume 300
3003 with water
If the tank in 40met above the ground
and the efficiency of the pump
not
find the electric power consumed by
the pump in filling
the tank
Answer:
The input power is [tex]44.4\times10^{3}\ kW[/tex]
Explanation:
Given that,
Time = 15 min
Volume of water = 30 m³
Height = 40 m
Efficiency = 30%
Density of water = 1000 kg/m³
Suppose, acceleration due to gravity = 10 m/s²
We need to calculate the mass of water pumped
Using formula of mass
[tex]Mass = Volume\times density[/tex]
Put the value into the formula
[tex]Mass=30\times1000[/tex]
[tex]Mass=3\times10^{4}\ kg[/tex]
We need to calculate the output power
Using formula of power
[tex]P_{out}=\dfrac{W}{t}[/tex]
[tex]P_{out}=\dfrac{mgh}{t}[/tex]
Put the value into the formula
[tex]P_{out}=\dfrac{3\times10^{4}\times10\times40}{15\times60}[/tex]
[tex]P_{out}=\dfrac{4}{3}\times10^{4}\ Watt[/tex]
We need to calculate the input power
Using formula of efficiency
[tex]\eta=\dfrac{P_{out}}{P_{in}}[/tex]
[tex]P_{in}=\dfrac{P_{out}}{\eta}[/tex]
Put the value into the formula
[tex]P_{in}=\dfrac{4\times100\times10^{4}}{3\times30}[/tex]
[tex]P_{in}=\dfrac{4\times10^{5}}{9}\ Watt[/tex]
[tex]P_{in}=44.4\times10^{3}\ kW[/tex]
Hence, The input power is [tex]44.4\times10^{3}\ kW[/tex]
If the spring constant is 10 N/m and the spring is stretched 1 m, what is the Force?
Answer:
10N
Explanation:
Applying the Hooke law:
F = kx
F: Force
k: stiffness coefficient
x: stretched distance
F = 10N/m x 1m = 10N
A dog is 10 m from a cat, whose speeds are 6 and 5 m / s, respectively. What time does the dog require to catch the cat?
Answer:
10 seconds
Explanation:
because the cat is moving one m/s slower than the dog, the dog has a relative speed of 1 m/s. 10 meters would take 10 seconds for the dog to cover
IMPORTANT 3 QUESTIONS!
Answer:
7. 20,000,000 mL.
8. 8,000 m.
9. 120,000 secs.
10. 4
Explanation:
7. Determination of the volume in millilitres (mL)
Volume in litre (L) = 20,000 L
Volume in millilitres (mL) =..?
The volume in mL can be obtained as follow:
1 L = 1,000 mL
Therefore,
20,000 L = 20,000 x 1,000 = 20,000,000 mL.
Therefore, 20,000 L is equivalent to 20,000,000 mL.
8. Determination of the distance in metre (m)
Distance in mile = 5 mile
Distance in metre =?
First, we shall convert from mile to kilometre.
This can be done as follow:
1 mile = 1.6 km
Therefore,
5 mile = 5 x 1.6 = 8 km
Finally, we shall convert 8 km to metre (m).
This is illustrated below:
1 km = 1,000 m
Therefore,
8 km = 8 x 1,000 = 8,000 m
Therefore, 5 miles is equivalent to 8,000 m.
9. Determination of the time in seconds.
Time = 400 minutes for 5 days.
First, we shall convert 400 mins to hour.
This is illustrated below:
60 minutes = 1 hour
Therefore,
400 mins = 400/60 = 20/3 hours
The time (hours) is 20/3 hours in 1 day.
Therefore, the time (hours) in 5 days will be = 20/3 x 5 = 100/3 hours.
Next, we shall convert 100/3 hours to minutes.
This is illustrated below:
1 hour = 60 minutes
Therefore,
100/3 hours = 100/3 x 60 = 2000 mins
Finally, we shall convert 2000 mins to seconds.
This is illustrated below:
1 mins = 60 secs
2000 mins = 2000 x 60 = 120,000 secs.
Therefore, the time is 120,000 secs.
10. Determination of the number of significant figures.
To obtain the significant figures of a number, we simply count all the numbers available.
Therefore, the number of significant figures for 9876 is 4.
Light travels at a speed of 2.998*108 m/s. Light takes approximately 3.25 minutes to travel from the Sun to reach a planet. Calculate the distance from the Sun to this planet in meters. Give your answer to 0 decimal places.
Answer:
585×10⁸ m
Explanation:
Distance = rate × time
d = (2.998×10⁸ m/s) (3.25 min) (60 s/min)
d = 585×10⁸ m
what type of image is formed by a lens if m = -0.87
A. The image is larger than the object and the image is real
B. The image is smaller than the object and the object is real
C. The image is larger than the object and is virtual
D. The image is smaller than the object and is virtual
Answer:
B.
Explanation:
as there is a '-' sign before the magnification value, it forms a real image.
so the last two options get cancelled.
as the value of magnification is 0.87 ie. lesser than 1, we can say that the image is smaller.
The type of image is formed by a lens if m = -0.87 would be smaller than the object and the object is real
What is a lens?A lens is a transmissive optical tool that employs refraction to focus or disperse a light beam. The power of the lens is expressed in the dioptre which is the reciprocal of the focal length of the lens.
The image formation through the lens is calculated with the help of the lens formula given as follows
1/f = 1/v - 1/u
where f is the focal length of the lens
u is the distance of the object from the lens
v is the distance of the image formed from the
magnification (m) = size of image /size of the object
As given in the problem image is formed by a lens if m = -0.87
Thus, the negative sign represents that the image formed by the object is real, and the magnitude of the magnification is less than 1 this represents that size of the image is smaller than the size of the object.
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n this activity, you will answer questions based on these two scenarios. Scenario 1 It’s the week before final exams, and Alicia is looking forward to graduation. However, she knows the week will be stressful. In addition to studying hard for her exams, her manager at work called and asked her to work an additional 15 hours. Her softball coach scheduled double practices to prepare for state finals. Her aunt has asked her to babysit her niece a few hours each night. On top of all this, she wants to spend some much-needed quality time with her friends. Alicia wishes there were 86 hours in a day instead of 24. Scenario 2 A small nation's economy depends on oil. The country’s earnings have declined greatly because of a recent drop in oil prices. The government uses these earnings to provide free education to all citizens under the age of 25. The country also uses its earnings to provide free health care and to provide benefits for retirees. The government also uses part of its earnings to help a neighboring country recover from a natural disaster. The president of the country imagines how much he could help his citizens if there weren’t any budget restrictions. Part A What do Alicia and the president have in common?
Answer: Alicia and the president do not have enough of a particular resource. Alicia doesn’t have enough time, and the president doesn’t have enough money.
Explanation: This is Plato's sample answer.
A cat stalks an unsuspecting mouse. The movement of the cat is shown in the following graph of the horizontal position, x, against time, t. What is the average speed of the cat between t = 2s and t = 6s?
Answer:
0.25 m/s
Explanation:
Average velocity = change in displacement / change in time
v = (1.5 m − 2.5 m) / (6 s − 2 s)
v = -0.25 m/s
The average speed is 0.25 m/s.
Answer:
0.25 m/s
Explanation:
khan academy
A 0.149 kg glider is moving to the right on a frictionless, horizontal air track with a speed of 0.710 m/s . It has a head-on collision with a 0.308 kg glider that is moving to the left with a speed of 2.27 m/s . Suppose the collision is elastic.1. Find the magnitude of the final velocity of the 0.157kg glider.
2. Find the magnitude of the final velocity of the 0.306kg glider.
Answer:
v1 = −2.201946 m/s ( to the left)
v2 = 0.7780534 m/s ( to the right)
Explanation:
Given the following :
Mass of first glider (m1) = 0.149kg
Initial Speed of first glider (u1) = 0.710 m/s
Mass of second glider (m2) = 0.308kg
Initial Speed of second glider (u2) = 2.27m/s
For elastic collision:
m1u1 + mu2u2 = m1v1 + m2v2
Where V1 and v2 = final velocities if the body after collision.
Taking right as positive ; left as negative
u1 = 0.710m/s ; u2 = - 2.27m/s
u1 - u2 = - (v1 - v2)
0.710 - - 2.27 = - v1 + v2
v2 - v1 = 2.98 - - - - (1)
From:
m1u1 + mu2u2 = m1v1 + m2v2
(0.149 * 0.710) + ( 0.308 * - 2.27) = (0.149 * v1) + (0.308 * v2)
0.10579 + (-0.69916) = 0.149 v1 + 0.308v2
−0.59337 = 0.149 v1 + 0.308v2
Dividing both sides by 0.149
v1 + 2.067v2 = −0.59337 - - - - - (2)
From (1)
v2 = 2.98 + v1
v1 + 2.067(2.98 + v1) = −0.59337
v1 + 6.16 + 2.067v1 = −0.59337
3.067v1 = −0.59337 - 6.16
3.067v1 = −6.75337
v1 = −6.75337 / 3.067
v1 = −2.201946 m/s ( to the left)
From v2 = 2.98 + v1
v2 = 2.98 + (-2.201946)
v2 = 0.7780534 m/s ( to the right)
what is space in detail?
Answer:
Space in the astronomy and cosmology space is 3 dimensional region and earth atmosphere end is called space.
Explanation:
Space is the everything of the top earth atmosphere moon, starts, milky way, black hole and GPS satellites an distant,space also called between stars,moon,planet.
Space is all the extends far in all directions, space is finite unbound space surface of the earth has finite are no beginning or not end.
Space contains there are three dimensions is called 3 D space,an space is to refer an interval during signal transmitted also used by the character, bytes, words and octets in digital signal.
space is that term can refer to various in science, communications and mathematics,and maintain orbits for responsible time, space is usually to begin at the lowest attitude satellites can maintain orbits.
space coordinates are uniquely define the location of any particular point and that continuum requires more than coordinates,and the number of dimensions and conventional space or digital communications during the signal represents logic is 0 words in a digital signal.
what is a hypothesis reffered to as after being verified by a large number or independent experiments
Answer:
The hypothesis may or may not be true and needs to be tested. It might be the answer to the problem. Hence, it must be tested thoroughly. When these predictions are tested again and again in independent scientific experiments and gets verified, the hypothesis is converted into a scientific theory.
A car is driving at 99 km/h, calculate the distance it travels in 70 minutes.
Give your answer in correct SI units rounded to 0 decimal places.
Answer:
The distance the car travels is 115500 m in S.I units
Explanation:
Distance d = vt where v = speed of the car and t = time taken to travel
Now v = 99 km/h. We now convert it to S.I units. So
v = 99 km/h = 99 × 1000 m/(1 × 3600 s)
v = 99000 m/3600 s
v = 27.5 m/s
The speed of the car is 27.5 m/s in S.I units
We now convert the time t = 70 minutes to seconds by multiplying it by 60.
So, t = 70 min = 70 × 60 s = 4200 s
The time taken to travel is 4200 s in S.I units
Now the distance, d = vt
d = 27.5 m/s × 4200 s
d = 115500 m
So, the distance the car travels is 115500 m in S.I units
If 5 complete oscillations of a sound wave pass through a point in 0.5 s and the speed of sound was recorded to be 10 m/s, then find the wavelength of the sound.
Answer:
λ = 2.5m
Explanation:
Given the following :
Speed of sound (v) = 10m/s
If 5 oscillations pass through a point in 0.5seconds;
Time taken (period) for 1 oscillation is :
Number of oscillations / total time taken
5 / 0.5 = 0.25 seconds
Wavelength, period and Velocity are related by the formula:
v = λ / T
λ = v * T
λ = 10 * 0.25
λ = 2.5 m
A stone of 1 kg is thrown with a velocity of 40 m/s across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice? *
A)16 N
B)-4 N
C)-16 N
Answer:
C)-16 N
Explanation:
concepts used
force = mass* acceleration
equation of motion
[tex]v^2 = u^2 + 2as[/tex]
where v is the final velocity
u is the initial velocity
and s is the distance moved
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Given
mass = 1 kg
initial velocity (u) = 40m/s
final velocity (v) = 0 as stones comes to rest
distance moved by stone (s) = 50m
using [tex]v^2 = u^2 + 2as[/tex]
[tex]0 = 40^2 +2a*50\\=> -1600 = 100a\\=> a = -1600/100 = -16[/tex]
Thus, acceleration is -16 m/s^2
here acceleration is negative as force of friction is opposing the motion.
Force of friction = mass of stone * acceleration of stone
Force of friction = 1*-16 kgm/s^2 = -16N ( kgm/s^2 = 1 N)
Thus, option c -16N is correct choice.
