Select the correct answer.
Which quantity is a vector quantity?
ОА. .
acceleration
OB.
mass
OC.
speed
O D.
volume
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Answer:
acceleration is the vector quantity because it depends on particular direction and has magnitude
Why is the time period of a charged particle in a uniform magnetic field independent of velocity??
Answer:
time period is independent of K.E of particle, it is inversely proportional to specific charge of the particle and it is independent of angle between velocity and magnetic field
Which statement about momentum is false? a. Momentum is a force b. Momentum may be transferred c. Momentum is always conserved d. Momentum is a property only of moving objects
Answer:
So, option(a).
Explanation:
Momentum is the measure of motion of the object.
Momentum is given by the product of mass and the velocity of the object.
(a) It is false.
(b) It is true, momentum is transferred.
(c) It is true, As the momentum of the system is conserved when no external force is applied on the system.
(d) It is true, as the momentum is associated with the velocity of the object.
the ratio of the energy per second radiated by the filament of a lamp at 250k to that radiated at 2000k, assuming the filament is a blackbody radiator? The filament of a particular electric lamp can be considered as a 90%blackbody radiator. calculate the energy per second radiated when its temperature is 2000k if its surface area is 10∧-6 m²
Answer:
(a) [tex]\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}[/tex]
(b) P = 0.816 Watt
Explanation:
(a)
The power radiated from a black body is given by Stefan Boltzman Law:
[tex]P = \sigma AT^4[/tex]
where,
P = Energy Radiated per Second = ?
σ = stefan boltzman constant = 5.67 x 10⁻⁸ W/m².K⁴
T = Absolute Temperature
So the ratio of power at 250 K to the power at 2000 K is given as:
[tex]\frac{P_{250k}}{P_{2000k}}=\frac{\sigma A(250)^4}{\sigma A(2000)^4}\\\\\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}[/tex]
(b)
Now, for 90% radiator blackbody at 2000 K:
[tex]P = (0.9)(5.67\ x\ 10^{-8}\ W/m^2.K^4)(1\ x\ 10^{-6}\ m^2)(2000\ K)^4[/tex]
P = 0.816 Watt
A football is projected at an angle of 30 from the ground with a n initial velocity of 10 m/s, take acceleration due to gravity is g= 10m/s2 .what is the time of flight
Answer: i dont know
Explanation:
Answer:
[tex]{ \bf \: time \: of \: flight : s = 0} \\ { \tt \: s \: is \: displacement} \\ \\ s = ut + \frac{1}{2} a {t}^{2} \\ 0 = u \sin( \theta) t - \frac{1}{2} g {t}^{2} \\ u \sin( \theta)t = \frac{1}{2} g {t}^{2} \\2 u \sin( \theta) = gt \\ { \boxed{ \tt{formular : time \: of \: flight = \frac{2u \sin( \theta) }{g} }}} \\ t = \frac{2 \times 10 \times \sin(30 \degree) }{10} \\ { \green{ \boxed{ \tt{ \bf{answer : { \tt{time \: of \: flight =1 \: second }}}}}}} \\ \\ { \tt{becker \: jnr}}[/tex]
what is the difference between static electricity produced by friction, conduction of electricity, and induction of an electrical charge?
Answer:
ummm a whole bunch
Explanation:
A HIGH SPEED TRAIN IS 180M LONG AND IT IS TRAVELLING AT 50M/S.HOW LONG WILL IT TAKE TO PASS A PERSON STANDING AT A LEVEL CROSSING?
B-HOW LONG WILL IT TAKE TO PASS COMPLETELY THROUGH A STATION WHOSE PLATFORMS ARE 220M IN LENGTH?
Answer:
a. Time = 3.6 seconds
b. Time = 4.4 seconds
Explanation:
Given the following data;
Distance = 180 m
Speed = 50 m/s
a. To find the time;
Speed can be defined as distance covered per unit time. Speed is a scalar quantity and as such it has magnitude but no direction.
Mathematically, speed is given by the formula;
[tex]Speed = \frac{distance}{time}[/tex]
Making time the subject of formula, we have;
[tex]Time = \frac{distance}{speed}[/tex]
Substituting into the equation, we have;
[tex]Time = \frac{180}{50}[/tex]
Time = 3.6 seconds
b. Distance = 220 meters
Speed = 50 m/s
To find the time;
[tex]Time = \frac{distance}{speed}[/tex]
Substituting into the equation, we have;
[tex]Time = \frac{220}{50}[/tex]
Time = 4.4 seconds
Claire rides her scooter to school, traveling 25 km/h. How much time in minutes does it take her to travel to her school, which is 4 km away ?
Answer:
9.6 minutes
Explanation:
We have that it takes Claire [tex]t=0.16h[/tex] amount of time to get to school
[tex]t=0.16h[/tex]
From the Question we are told that
Velocity[tex]v= 25 km/h.[/tex]
Distance [tex]d=4km[/tex]
Generally the equation for Time is mathematically given as
[tex]v=\frac{d}{t}\\\\t=\frac{4}{25}\\\\t=0.16h[/tex]
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a student drops a ball off the top of building and records that the ball takes 3.32s to reach the ground (g=9.8 m/s^2). what is the ball's speed just before hitting the ground?
Answer:
Explanation:
Use the one-dimensional equation for motion
v = v₀ + at and filling in,
v = 0 + (-9.8)(3.32) so
v = -33 m/s (negative because it is going downwards and upwards is positive).
pleaase help me i don't know this !!!
Answer:
coefficient=1.09N/m×g
coefficient=1.09N/0.413g×10m/s square
coefficient=1.09N/4.13N
coefficent=0.263
f= uK
here f is force, u is cofficient of friction , k is normal force
k = mg
f = umg
1.09 = u × 0.41 × 10
u = 1.09 ÷ 4.1
u = 0.26
Which type of radiation can reach the furthest?
A. Beta
B. Gamma
C. Alpha
Answer:
B. Gamma
Explanation:
The gamma radiation can travel much farther through air than alpha or beta.
A 4 mm object is observed by a magnifying lens as 1.25 cm. Calculate the ratio do/di.
Answer:
dₒ/dᵢ = 0.32
Explanation:
From the question given above, the following data were obtained:
Object height (Hₒ) = 4 mm
Image height (Hᵢ) = 1.25 cm
Ratio of object distance (dₒ) to image distance (dᵢ) [dₒ/dᵢ] =?
Next, we shall convert 4 mm to cm. This can be obtained as follow:
10 mm = 1 cm
Therefore,
4 mm = 4 mm × 1 cm / 10 mm
4 mm = 0.4 cm
Next, we shall determine the magnification of the lens. This can be obtained as follow:
Object height (Hₒ) = 4 mm
Image height (Hᵢ) = 1.25 cm
Magnification (M ) =?
M = Hᵢ/Hₒ
M = 1.25 / 0.4
M = 3.125
Finally, we shall determine the ratio of object distance (dₒ) to image distance (dᵢ). This can be obtained as follow:
Magnification (M) = 3.125
Ratio of object distance (dₒ) to image distance (dᵢ) [dₒ/dᵢ] =?
Magnification (M) = image distance (dᵢ) / object distance (dₒ)
M = dᵢ/dₒ
Invert
1/M = dₒ/dᵢ
1/3.125 = dₒ/dᵢ
dₒ/dᵢ = 0.32
Therefore, the ratio of object distance (dₒ) to image distance (dᵢ) [dₒ/dᵢ] is 0.32
when is the acceleration of body is positive negative and zero?
Answer:
【 In vector form , if angle between velocity vector and acceleration vector is less than 90° and greater than 0° then it is positive acceleration and if it is less than 180° and greater than 90° then it is negative acceleration. If there is no acceleration vector then it is called zero acceleration. 】
Two tuning forks, 492 Hz and 498 Hz, are struck simultaneously. How many beats will be heard?
none
2.00 beats
4.00 beats
6.00 beats
Answer:
6 beats
If one fork beats once and another twice in the same time period
you would hear 1 beat. (Same for 2 and 3 beats).
Object A has twice the mass of object B. Both objects are moving at the same speed. Which accurately describes how inertia relates to Newton’s second law of motion in this example? Object A has twice the mass of object B. Both objects are moving at the same speed.
A. Object A requires twice the force to stop as Object B.
B. Object A requires one-and-a-half times the force to stop as Object B.
C. Object A requires four times the force to stop as Object B.
Answer:
A. Object A requires twice the force to stop as Object B.
Explanation:
Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.
Newton's Second Law of Motion states that the acceleration of a physical object is directly proportional to the net force acting on the physical object and inversely proportional to its mass.
Mathematically, it is given by the formula;
[tex] Acceleration = \frac {Net \; force}{mass} [/tex]
Let's assume the following values;
Mass of object B = 10 kg
Mass of object A = 2 * B = 2 * 10 = 20 kg
Acceleration = 5 m/s²
I. To find the force for B;
[tex] Force = mass * acceleration [/tex]
[tex] Force = 10 * 5 [/tex]
Force B = 50 Newton
II. To find the force for A;
[tex] Force = mass * acceleration [/tex]
[tex] Force = 20 * 5 [/tex]
Force A = 100 Newton
From the calculation, we can deduce that Force A (100 N) is twice or double the value of Force B (50 N).
In conclusion, since object A has twice the mass of object B and both objects are moving at the same speed, object A would require twice the force to stop as Object B.
I need help answer these questions please
Answer:
1. 25 J
2. 250 J
3. 900,000 J
4. 7,500 J
Explanation:
1. The distance the wheelbarrow is tilted, d = 0.5 m
The force used to tilt the wheelbarrow, F = 50 N
The work done, W = F × d
∴ W = 50 N × 0.5 m = 25 J
2. Work done, W = Force × Distance
The applied force, F = 50 N
The distance the sand is moved, d = 5 m
∴ W = 50 N × 5 m = 250 J
3. The work done, W = The load lifted × The height to which the load is lifted
∴ W = 90,000 N × 10 m = 900,000 J
The work done, W = 900,000 J
4. The work output of the skateboard = The work input × Efficiency
Given that the skateboard is an ideal machine, we have;
The work output of the skateboard = The work input = W
W = F × d
F = 15 N, d = 500 m
∴ W = 15 N × 500 m = 7,500 J
The work output of the skateboard = W = 7,500 J.
A pole-vaulter first converts kinetic energy into
a. thermal energy.
b. chemical energy. mechanical energy.
c. mechanical energy
d. elastic potential energy.
Answer:
d. elastic potential energy
A cheetah runs at a speed of 27.6 m/s. If the
cheetah runs for 9.30 s, what is the distance the
cheetah runs? Show all your work.
Answer:
256.68m
Explanation:
that is the procedure above
A cheetah runs at a speed of 27.6 m/s. If the cheetah runs for 9.30 s, then the distance covered by the cheetah would be 256.68 metes
What is speed?The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object. The unit of speed is meter/second. The generally considered unit for speed is a meter per second.
The mathematical expression for speed is given by
speed = distance /Total time
As given in the problem A cheetah runs at a speed of 27.6 m/s. If the cheetah runs for 9.30 s, we have to calculate the distance covered by the cheetah
Distance=?
speed=27.6 m/s
time= 9.30 s
speed = distance /Total time
27.6 m/s = Distance /9.30 s
Distance = 27.6×9.30
=256.68 metes
Thus, the distance covered by the cheetah would be 256.68 metes
Learn more about speed from here
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Which has greater kinetic energy, a car traveling at 40 mph or a half-as-massive car traveling at 80 mph?
a
-The 40 mph car
-The 80 mph car
-Both have the same kinetic energy
-Neither has kinetic energy
Answer:
The 80 mph car
Because the formula says 1/2 mass but for the velocity it is squared
In what way is Height related to Potential Energy?
Explanation:
Lets say you have a ball in your hand, you raise your hand to just above your head. Now, when you did that you created potential energy that is ready to be released. you drop the ball and the ball bounces a few times off the ground. Now lets say you got a ladder and doubled the ball's height doubling the energy now stored in the ball, when you drop it the ball should bounce much higher after hitting the ground as a result of more energy being released.
Hope this helped.
mechanical energy that has been "lost" to friction has actually been destroyed.
Answer:
Yes
Explanation:
The friction is bigger than the mechanical energy so it kind off takes over the mechanical energy. but if the friction decreases mechanical energy can work on the object again
Eratosthenes measured the circumference of Earth to within 4% of the correct value
A. Looking at stick shadows on the equinox.
B. Noting how much more of the celestial sphere came into view when walking south.
C. Sighting the stars from within the deepest well in Egypt on the day of the solstice.
D. Using the detailed reports of far-sailing mariners
Answer:
A. Looking at stick shadows on the equinox.
Explanation:
He measures the circumference by placing a pole when the sun is overhead on the days of solstice. He determined the circumference by measuring the difference between Alexandria to Syene and the angle of the pole's shadow.
The equation used for the calculation of circumference is as follow
[tex]\frac{360 degrew}{7.2 degree} = \frac{Circumference of earth}{Distance from Alexandria to Syene}[/tex]
Please refer to the following link for more details
https://www.khanacademy.org/humanities/big-history-project/solar-system-and-earth/knowing-solar-system-earth/a/eratosthenes-of-cyrene
How long will it take the cart to to travel 2.8m, starting from rest?
Answer:
0.748seconds
Explanation:
s = 1/2 *g*t^2
2.8 = 1/2 * 10* t^2
5.6 = 10 * t^2
0.56 = t^2
t = √0.56
t = 0.7483seconds
"" damped force equation ""
Answer:
In many vibrating systems the frictional force Ff can be modeled as being proportional to the velocity v of the object: Ff = −cv, where c is called the viscous damping coefficient.
Which instrument changes kinetic energy into electrical energy?
electric motor
hair drier
electric bell
dynamo
Answer:
Dynamo
Explanation:
As we all know, there are dynamos in bicycles. When we paddle the cycle, the wheels of the cycle rotates by generating kinetic energy. When the wheels rotate, the dynamo starts to rotate. This makes the motor inside the dynamo rotates and generate electrical energy.
The drone can fly for 25 minutes before the battery needs recharging.
The power output of the battery is 65.0 W
Calculate the maximum energy stored by the battery.
Answer:
105.6 KJ
Answer
3.7/5
4
hope this will help you friend.
who is the father of computer but not Charles Babbage can anyone guess
Answer:
It's Obusively charles Babbage I guess
A constant unbalanced force is applied to an object for a period of time. What will happen to the objects acceleration?
a. It will accelerate in the direction of the net force.
b. It will accelerate opposite the direction net force.
c. There is no acceleration.
d. Not enough information to answer
Answer:
A
Explanation:
The moving object will accelerate as long as a net force is applied. If a net force is not applied, the object will continue to move at a constant speed along the same path in curved spacetime (due to gravity). If the net force continues the velocity of the object will continue to increase until nearly reaching the limit (speed of light).
A train starts from rest and leaves Greenburg station with an acceleration of 1.20 meters per second2. How long does it take the train to travel a distance of 500 meters?
Answer:
Time, t = 28.87 seconds
Explanation:
Given the following data;
Acceleration = 1.20 m/s²
Distance = 500 meters
Initial velocity = 0 m/s
To find the time to cover the distance, we would use the second equation of motion;
[tex] S = ut + \frac {1}{2}at^{2}[/tex]
Where;
S represents the displacement or height measured in meters.
u represents the initial velocity measured in meters per seconds.
t represents the time measured in seconds.
a represents acceleration measured in meters per seconds square.
Substituting into the equation, we have;
[tex] 500 = 0*t + \frac {1}{2}*(1.2)*t^{2}[/tex]
[tex] 500 = 0 + 0.6*t^{2} [/tex]
[tex] 500 = 0.6t^{2} [/tex]
[tex] t^{2} = \frac {500}{0.6} [/tex]
[tex] t^{2} = 833.33 [/tex]
Taking the square root of both sides, we have;
[tex] t = \sqrt{833.33} [/tex]
Time, t = 28.87 seconds
The density of oil is 0.8 g/cm^3. What is the mass of 36 cm^3 of oil? + (1 Point) O 0.29 N O 28.09 28.8 g O 36.89
Answer:
density = mass/volume
density=0.8
volume=36
mass=?
0.8=mass/36
mass = 36x0.8=28.8g
