1. What is the best way to determine levelness?
Plot Position versus Time and compare the linear fit from each direction of travel; slopes should be equal.
See if the Acceleration versus Time for both directions are both zero.
Plot the Acceleration versus Time for one direction and acceleration should be zero.
See if slope of Velocity versus Time for both directions are equal but opposite.
Plot Position versus Time and compare the linear fit from each direction of travel; slopes should be equal but opposite.
Plot Velocity versus Time for both directions; slopes should be equal.
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2. In chronological order, what happens to the kinetic, potential, and total energy of the cart for one half cycle. The half cycle starts just after you have pushed the cart. The half cycle finishes just when the cart stops at the height of its motion. Remember, this is about the cart's mechancial energy.
Kinetic goes from maximum to zero (at the highest point of the incline.)
Potential goes from zero to a maximum slightly less than Kinetic's maximum.
Total Energy stays the same, but decreases slightly due to friction.
Kinetic goes from maximum to zero (at the highest point of the incline.)
Potential goes from zero to a maximum slightly less than Kinetic's maximum.
Total Energy rises as the cart gains altitude on the incline.
Kinetic goes from zero to maximum (at the highest point of the incline.)
Potential goes from maximum to zero since the cart has stopped.
Total Energy stays "the same," but decreases slightly due to friction.
Kinetic goes from zero to maximum (at the highest point of the incline.)
Potential goes from maximum to zero since the cart has stopped.
Total Energy rises as the cart gains altitude on the incline.
Kinetic stays constant because the cart is moving.
Potential starts out high because it has motion at the beginning and then goes to zero a the top since it stops.
Total Energy goes down because the cart is slowing down as it climbs the incline.
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3. What word (four letters long that starts with a w) describes the transfer of potential energy into kinetic energy?
(Use all lower case.)
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4. Which situation has the greatest net force along incline?
the net force is always the same for an incline, f = mgcosθ
the net force is always the same for an incline, f = mgsinθ
when the cart is going downhill
when the cart is going uphill
when the cart is at rest
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5. What are the units for energy?
kg m2s-2
All three units described here are valid for Energy.
None of these three units works.
Joule
N m
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6. Let's say you measure an average acceleration to be 0.4241 ms-2.
What is the height (in centimeters) of the riser block?
Assume the legs of the track span 1.0000 m and that there is neither friction nor drag. Also assume the block is under one of the legs.
cm
Use three significant figures or N/A if not enough information is given.
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7. You have a level track. You push a cart with mass = 0.88[kg].
You measure the initial velocity to be 0.78[m s-1].
2 seconds later, you measure the velocity to be 0.585[m s-1].
What is the work (reported in mJ) that friction did on the cart?
work = [mJ]
Use three sig. figs. or N/A if not enough information is given, such as change in position! Remember, that if the system gains energy, then positive work is done; otherwise work < 0.
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8. You have a different system of unknown cart mass upon a level surface. The cart travels 55 [cm] in an unknown time period. The change in Kinetic Energy is -0.117117 [J]. What is the force of friction measured in Newtons?
[N]
Use three sig. figs. or N/A if not enough information is given, such as time, and mass! Don't worry about the sign of friction.
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I will be happy to critique your thinking.
Perhaps if you divide up the questions to different postings and add your answers, we will then be able to comment.
1. What is the best way to determine levelness?
See if slope of Velocity versus Time for both directions are equal but opposite.
2. In chronological order, what happens to the kinetic, potential, and total energy of the cart for one half cycle. The half cycle starts just after you have pushed the cart. The half cycle finishes just when the cart stops at the height of its motion. Remember, this is about the cart's mechancial energy.
Kinetic goes from maximum to zero (at the highest point of the incline.)
Potential goes from zero to a maximum slightly less than Kinetic's maximum.
Total Energy stays the same, but decreases slightly due to friction
3. What word (four letters long that starts with a w) describes the transfer of potential energy into kinetic energy?
work
4. Which situation has the greatest net force along incline?
when the cart is at rest
5. What are the units for energy?
All three units described here are valid for Energy
6. Let's say you measure an average acceleration to be 0.4241 ms-2.
What is the height (in centimeters) of the riser block?
Assume the legs of the track span 1.0000 m and that there is neither friction nor drag. Also assume the block is under one of the legs.
Answer not known
7. You have a level track. You push a cart with mass = 0.88[kg].
You measure the initial velocity to be 0.78[m s-1].
2 seconds later, you measure the velocity to be 0.585[m s-1].
What is the work (reported in mJ) that friction did on the cart?
work =200 [mJ]
8. You have a different system of unknown cart mass upon a level surface. The cart travels 55 [cm] in an unknown time period. The change in Kinetic Energy is -0.117117 [J]. What is the force of friction measured in Newtons?
[N]
N/A sufficient data not given
1-5 right
6 I don't understand
7 I didn't get that, it looks as if you rounded to one sig digit
8
f*.55=change in KE.
Thanks Bobpursley.
Prob.7
a = v-u / t = (0.585 - 0.780)/2 = 0.0975ms-2
S = ut + at2/2 = 0.78*2 - (0.0975*4)/2 = 1.56 - 0.195 = 1.36Work done by friction = m*a*S = 0.88*0.0975*1.365 =0.117117 J = 117.117 mJ
Will anyone help in solving prob.6?
for problem six you just divide the average acceleration multiplied by 1.0m by gravity.
(accelgrav)(1.0m)/(9.8) = You should get 4.12 or something :)
n/A
Question 4 is:
When the cart is going uphill. In this scenario (for this lab) the force that pushed the cart uphill is no longer in play. So the only forces acting on the cart are mgSin(theta) and friction, both of which are pointing in the same direction when the cart is going up hill, giving it the highest overall net force.
Question 1The best way to determine levelness is to see if slope of velocity versus time for both directions are equal but opposite.
Question 4:The greatest magnitude of net force is when the cart is going uphill. Uphill has a Net force greater by twice friction. It is not when the cart is at rest.
Question 6: mgsin(theta) = ma. Use to solve for theta, the angle. Then take the tangent of the angle to solve for h.
Question 8: There is enough info. Take the change in kinetic energy given in the problem and divide by the distance in the problem using the correct units. If the answer is in Newtons change your distance given in cm to the distance in meters before dividing.
1. The best way to determine levelness is to plot Position versus Time and compare the linear fit from each direction of travel. The slopes should be equal. This will show if the cart is maintaining a constant level position as it moves. Additionally, you can also check if the Acceleration versus Time for both directions is zero. If the acceleration is zero, it indicates that the cart is not moving up or down, which suggests levelness. Finally, you can plot the Velocity versus Time for both directions and check if the slopes are equal but opposite. If the slopes are equal but opposite, it indicates that the cart is maintaining a constant velocity in both directions, which suggests levelness.
2. In chronological order, for one half cycle starting just after you have pushed the cart and finishing when the cart stops at the height of its motion, the kinetic energy goes from maximum to zero (at the highest point of the incline.), the potential energy goes from zero to a maximum slightly less than kinetic energy's maximum, and the total energy stays the same but decreases slightly due to friction. This is because as the cart moves up the incline, its kinetic energy decreases while its potential energy increases. However, some of the energy is lost to friction, causing a slight decrease in the total energy.
3. The word that describes the transfer of potential energy into kinetic energy is "work".
4. The situation that has the greatest net force along incline is when the cart is going downhill. This is because when the cart is going downhill, the component of gravity acting along the incline (mg sinθ) is added to the force due to friction, resulting in a greater net force.
5. The units for energy are Joule (J). However, kg m2s-2 and N m are also valid units for energy.
6. To determine the height of the riser block, we need the acceleration and the length of the track span. Unfortunately, the given information does not include the required values, so we cannot calculate the height of the riser block.
7. To calculate the work that friction did on the cart, we need the mass of the cart, the initial velocity, the final velocity, and the change in position. However, the given information only includes the mass and the initial and final velocities. Without the change in position, we cannot calculate the work done by friction.
8. To calculate the force of friction, we would need the mass of the cart and the time period. Without this information, we cannot calculate the force of friction.