49. A block is pushed across a horizontal surface with a
coefficient of kinetic friction of 0.15 by applying a
150 N horizontal force.
(a) The block accelerates at the rate of 2.53 m/s2
Find the mass of the block.
(b) The block slides across a new surface while
experiencing the same applied force as before.
The block now moves with a constant speed.
What is the coefficient of kinetic friction between
the block and the new surface?
Answer:
(a) 37.5 kg
(b) 4
Explanation:
Force, F = 150 N
kinetic friction coefficient = 0.15
(a) acceleration, a = 2.53 m/s^2
According to the newton's second law
Net force = mass x acceleration
F - friction force = m a
150 - 0.15 x m g = m a
150 = m (2.53 + 0.15 x 9.8)
m = 37.5 kg
(b) As the block moves with the constant speed so the applied force becomes the friction force.
[tex]F = \mu m g \\\\150 = \mu\times 37.5\\\\\mu = 4[/tex]
The summer camps had a field trip from the campus to Fragrance Hill. They traveled at an average speed of 65 km/h in the first 2 hours. After that, traveled at another average speed of 78 km/h. If the distance between the campus and Fragrance Hill is 364 km, what was the total time for the field trip?
Answer:
Explanation:
They traveled this distance in 2 parts, essentially. Part 1 had an average speed for a certain number of hours, part 2 had an average speed for a certain number of hours, and those 2 parts taken together took them a distance of 364 km. In equation form, that looks like this:
km/hr part 1 + km/hr part 2 = 364 km
Now we need to find each part on the left side of that equation. Part 1 first:
We traveled 65 km/hr for 2 hours, so that took us
[tex]65\frac{km}{hr}*2hr[/tex] and canceling out the hour label, we have that in part 1 we got
65(2) = 130 km. Good. Now onto the second part, where our unknown is.
We traveled 78 km/hr the second part for x hours, so that took us
[tex]78\frac{km}{hr}*xhr[/tex] and canceling out the hour label, we have that in part 2 we got
78x km. Now we can fill in the main equation (the one in bold print)
130 km + 78x km = 364 km and subtracting 130 km from both sides:
78x km = 234 km and dividing by 78 km:
x = 3 hours. Part 2 took 3 hours. Part 1 took 2 hours, so the whole trip took 5 hours.
When an object is in a gravitational field, it has energy in its __________ __________ energy store.
Answer:
Gravitational potential
Explanation:
Any object that is not on the surface of the Earth, but at a height instead has potential energy. Eventually, this can become kinetic energy once the object falls.
When an object is in a gravitational field, it has energy in its gravitational potential energy store.
The mass of a brick is 2kg. Find the mass of water displaced by it when it is completely immersed in water. (Density of the bricks is 2.5 g/cm^3)
Answer:
2000g
Explanation:
volume=mass/density
=2000/2.5
=800cm³
mass=density×volume
=800×2.5
=2000g
The gravitational force acting on various masses is measured on different planets. Measured values for the forces acting on the corresponding masses are shown in the data table. Analyze the data and develop a method for comparing the gravitational field strengths on the different planets. Use your method to compare the gravitational field strengths, and report your conclusions.
The boiling point of water is 1000 C at sea level. The boiling point of butane is -1.50C… If we leave liquid butane in a bowl on a table in a room where the temperature is 240C, butane will
A. evaporate.
B. condense.
C. freeze.
D. melt.
Answer: If we leave liquid butane in a bowl on a table in a room where the temperature is [tex]24^{o}C[/tex], butane will evaporate.
Explanation:
A temperature at which the the liquid and gaseous phase of a substance of a substance are present in equilibrium with each other is called boiling point.
For example, the boiling point of butane is -1.5 degree Celsius.
This means that at a temperature above -1.5 degree Celsius, butane will exist is gaseous state. That is, at a temperature of 24 degree Celsius butane will evaporate.
Thus, we can conclude that if we leave liquid butane in a bowl on a table in a room where the temperature is [tex]24^{o}C[/tex], butane will evaporate.
HELPPPPPPPPPPP PLEASEEEEEEEEEEE
Complete this sentence. The solubility of a sample will ____________ when the size of the sample increases.
stay the same
decrease
increase
be unable to be determined
the answer is not decrease
The solubility of the sample will decrease
Which labels are correct for the regions marked? a. X: Slower in gases than liquids Y: Faster in solids than gases Z: Velocity depends on medium b. X: Faster in gases than liquids Y: Slowest in solids Z: Faster in liquids than gases c. X: Slower in solids than liquids Y: Velocity depends on medium Z: Faster in liquids than gases d. X: Velocity depends on medium Y: Fastest in gases Z: Slower in liquids than solids
Answer:
a. X: Slower in gases than liquids Y: Faster in solids than gases Z: Velocity depends on medium.
Explanation:
Speed of sound is fastest in solids. Sound waves travel more quickly in solid, than of liquid and gases. Sound waves travel most slowest in gases. Speed of sound varies significantly and it depends upon medium it is travelling through. In more rigid medium sounds velocity will be faster.
please answer quick for brainlist ; )
Answer:
The diagram assigned B
explanation:
Check the direction of the two vectors, their resultant must be in the same direction.
A basketball is shot by a player at a height of 2.0m. The initial angle was 53° above the horizontal. At the highest point, the ball was travelling 6 m/s. If he scored (the ball went through the rim that is 3.00m above the ground), what was the player's horizontal distance from the basket?
At the ball's highest point, it has no vertical velocity, so the 6 m/s is purely horizontal. A projectile's horizontal velocity does not change, which means the ball was initially thrown with speed v such that
v cos(53°) = 6 m/s ==> v = (6 m/s) sec(53°) ≈ 9.97 m/s
The player shoots the ball from a height of 2.0 m, so that the ball's horizontal and vertical positions, respectively x and y, at time t are
x = (9.97 m/s) cos(53°) t = (6 m/s) t
y = 2.0 m + (9.97 m/s) sin(53°) t - 1/2 gt ²
Find the times t for which the ball reaches a height of 3.00 m:
3.00 m = 2.0 m + (9.97 m/s) sin(53°) t - 1/2 gt ²
==> t ≈ 0.137 s or t ≈ 1.49 s
The second time is the one we care about, because it's the one for which the ball would be falling into the basket.
Now find the distance x traveled by the ball after this time:
x = (6 m/s) (1.49 s) ≈ 8.93 m
PLEASE HEEEEEEELP
Assume that the velocity of the soda bottle falling from a height of 0.8 m will be 4 m/s. Record this velocity for each mass in Table A, and use it in calculating the predicted kinetic energy of the soda bottle for the masses of 0.125 kg, 0.250 kg, 0.375 kg, and 0.500 kg using the equation: KE=1/2 mv^2 When solving for kinetic energy (KE), m is mass, and v is the speed (or velocity).
KE = (0.5) m v²
given that : v = speed of the bottle in each case = 4 m/s when m = 0.125 kg
KE = (0.5) m v² = (0.5) (0.125) (4)² = 1 J
when m = 0.250 kg KE = (0.5) m v² = (0.5) (0.250) (4)² = 2 J
when m = 0.375 kg KE = (0.5) m v² = (0.5) (0.375) (4)² = 3 J
when m = 0.0.500 kg KE = (0.5) m v² = (0.5) (0.500) (4)² = 4 J
The direction equivalent to {40° W of S} is:
A. 40 ° E of S
B. 40° W of N
C. 40° E of N
D. 50° S of W
E. 50° E of N
Answer:
c
Explanation:
Drag each label to the correct location on the image. Identify the particles and characteristics on this model of an atom.
Positively charged
Electron
Proton
Neutron
Negatively charged
Answer:
cant see picture
Explanation:
Answer:
please add picture so i can help you
Explanation:
Example to measure the interval of time of a small stone dropped from 1m height.
Answer:
The time required is 0.45 s.
Explanation:
Height, h = 1 m
initial velocity, u = m/s
Let the time is t.
Use second equation of motion
[tex]h = u t + 0.5 at^2\\\\1 = 0 +0.5 \times 9.8 \times t^2\\\\t = 0.45 s[/tex]
What is the volume of a cone with a height of 27 cm
and a radius of 13 cm? Round your answer to the
nearest tenth.
Use the button on your calculator to complete this
problem.
V =
cm?
Explanation:
→ Volume of cone = πr² × h/3
Here,
Radius (r) = 13 cmHeight (h) = 27 cm→ Volume of cone = π(13)² × 27/3 cm³
→ Volume of cone = 169π × 9 cm³
→ Volume of cone = 1521π cm³
→ Volume of cone = 1521 × 22/7 cm³
→ Volume of cone = 33462/7 cm³
→ Volume of cone = 4780.28 cm³
Answer:
4,778.4 is correct
Explanation:
What does the m stand for in the enthalpy equation?
Answer:
Use the formula ∆H = m x s x ∆T to solve.
Explanation:
Once you have m, the mass of your reactants, s, the specific heat of your product, and ∆T, the temperature change from your reaction, you are prepared to find the enthalpy of reaction. Simply plug your values into the formula ∆H = m x s x ∆T and multiply to solve.
satellite does not need any energy to revolve around the earth why
Answer:
An artificial satellites revolves around the earth under the influence of its gravitational force. So it does not require any energy to revolve around energy.
or maybe god:)))(
A student initially 10.0 m East of his school walks 17.5 m West. The magnitude of the student's displacement, relative to the school is _________ m? The direction of the student's displacement, relative to the school is ______?
Answer:
1. 7.5 m
2. towards west side
explanation:
I hope it will help you
79. A skater glides along a circular path of radius 5.00 m in clockwise direction. When he coasts around one-half of the circle, starting from the west point, find (a) the magnitude of his displacement vector and (b) how far he actually skated. (c) What is the magnitude of his displacement vector when he skates all the way around the circle and comes back to the west point
The potential difference across a resistor increases by a factor of 4. How
does the current change? (Ohm's law: V = IR)
A it increases by a factor of 4
B it decreases by a factor of 4
C it increases by a factor of 2
D it decreases by a factor of 2
Answer:
Correct option is C it decreases by a factor of 2
Answer: A - it increases by a factor of 4
Explanation:
Ohm's law is V = IR where V = potential difference, I = current, and R = resistance. Assuming that resistance stays constant (since the question mentioned no change in resistance), we only need to look at "V" and "I" in the equation V = IR.
"V" and "I" are directly proportional. In other words, whatever change happens to "V" will also occur to "I". Since "V" increases by a factor of 4, then "I" will also increase by a factor of 4.
You could also approach this problem by plugging in a change of 4 for the potential difference in the equation: V = I*R.
If we plug in 4V for V, we now have:
4V = I*R
Since the left side increases by a factor of 4, then the right side (only looking at current in this case) will also need to increase by a factor of 4 in order to have the right side stay equal to the left. Therefore, current will also increase by a factor of 4.
True or false: Ultimate tensile strength increases as the thickness of a solid material sample increases.
True
False
Answer:
False.
Explanation:
Tensile strength should remain constant, regardless of thickness. For larger cross sections, it can slightly increase because the atoms in the center become more constricted and therefore less responsive to the applied stress.
Answer:
Tensile strength should remain constant, regardless of thickness. For larger cross sections, it can slightly increase because the atoms in the center become more constricted and therefore less responsive to the applied stress.FALSE
what means 10² what we call this
we call it as well as 100 . so easey
Answer:
10 squared
Explanation:
10 squared
In Depth:
Let have a square that has a side length of 10.
A square four sides are equal and if we find the area of a squared, our formula is
[tex] {s}^{2} [/tex]
Our in this instance,
[tex] {10}^{2} [/tex]
or we call it
[tex]10 \: \: squared[/tex]
Using your Periodic Table, which of the following elements below has the largest atomic radius? A.) Aluminum B.) Sodium C.) Sulfur, D.) Fluorine
Answer:
sodium
Explanation:
it is highly reactive metal.
Answer:
aluminium
Explanation:
In a period , as we go from left to right in a periodic table, atomic number increases .
Differentiating electrons enters into same shell hence the effective nuclear charge decreases .
Hence atomic radius decreases along period.
Conculsion:
Aluminium is the element which has greater atomic radius and sulphur has smaller atomic radius.
PLS HELP ME I DONT HAVE MUCH TIME LEFT
The Euler buckling load of a 160-cm-long column will be _____ times the Euler buckling load of an equivalent 120-cm-long column.
1.78
0.56
0.75
2.37
1.33
0.42
Calculate the minimum area moment of inertia for a rectangular cross-section with side lengths 3 cm and 8 cm.
201 cm4
18 cm4
128 cm4
4 cm4
24 cm4
Answer:
A certain source of 12V with an internal resistance 1colomb is connected to 5colomb external resistance what is the current
write some uses of magnetic force
Answer:
television,radios, microwave ovens, telephone system and computer
Which model of the universe is the most widely accepted, and what does it
predict?
Compression and rarefaction are commonly used with longitudinal waves. And Crests and trough is commonly used with transverse waves!
Answer:
yes Compression and rarefaction are commonly used with longitudinal waves. And Crests and trough are commonly used with transverse waves!
Explanation:
The world’s tallest building is the Burj Khalifa which stands at 828 m above the ground. An eccentric billionaire CEO has an office on the top floor. He insists on having a personal elevator installed that consists only of a giant spring that spans from the basement to his office when it is uncompressed. If his mass is 120 kg, what spring constant in N/m is required so that he momentarily comes to rest on the ground floor?
Answer:
The spring constant is approximately 2.84 N/m
Explanation:
The height of the building, h = 828 m
The mass of the billionaire that has an office on the top floor, m = 120 kg
Gravitational potential energy, P.E. = m·g·h
Where;
g = The acceleration due to gravity ≈ 9.81 m/s²
The gravitational potential energy of the billionaire at the top floor is therefore;
P.E. of billionaire at top floor = 120 kg × 9.81 m/s² × 828 m = 974,721.6 J
The elastic potential energy of the spring, [tex]P.E._{spring}[/tex] is given as follows;
[tex]P.E._{spring} = \dfrac{1}{2} \cdot k \cdot h^2[/tex]
Where;
k = The spring constant of the spring in N/m
h = The extension of the spring = The height of the building = 828 m
Given that the energy of the spring is conserved, we have;
[tex]P.E._{spring}[/tex] = P.E. of billionaire = 974,721.6 J
Plugging in the values gives;
[tex]P.E._{spring} = 974,721.6 \ J = \dfrac{1}{2} \times k \times (828 \ m)^2[/tex]
Therefore;
2*974,721.6/(828^2)
[tex]k = \dfrac{2 \times 974,721.6 \ J}{(828 \ m)^2} \approx 2.84 \ N/m[/tex]
The spring constant, k ≈ 2.84 N/m.
In practice, if a voltmeter was connected across any combination of the terminals, the potential difference would be less than what is calculated. State why this is so and explain how the difference is kept to a minimum in modern transformers.
Answer:
This difference is kept to a minimum because the resistance in transformers is a few tens of ohms and the resistance of modern voltmeters is of the order of MΩ.
Explanation:
A voltmeter is built by a galvanometer and a resistance in series, this set is connected in parallel to the resistance where the voltage is to be measured, therefore the voltage is divided between the voltmeter and the element to be measured, consequently the measured voltage It is less than the calculated one, since for them the resistance of the voltmeter is assumed infinite.
This difference is kept to a minimum because the resistance in transformers is a few tens of ohms and the resistance of modern voltmeters is of the order of MΩ.
Help help please !!!!!!!!!!!!!!!!
Answer:
You need time buddy
Explanation:Exactly honest
