Question

Where's the Energy?

Need help with concepts in the problem below!
In this problem, we will consider the following situation as depicted in the diagram (Figure 1) : A block of mass m slides at a speed v along a horizontal, smooth table. It next slides down a smooth ramp, descending a height h, and then slides along a horizontal rough floor, stopping eventually. Assume that the block slides slowly enough so that it does not lose contact with the supporting surfaces (table, ramp, or floor).

You will analyze the motion of the block at different moments using the law of conservation of energy.

Where's the Energy? Need help with concepts in the problem below! In this problem, we will consider the following situation as depicted in the diagram (Figure 1) : A block of mass m slides at a speed v along a horizontal, smooth table. It next slides down a smooth ramp, descending a height h, and then slides along a horizontal rough floor, stopping eventually. Assume that the block slides slowly enough so that it does not lose contact with the supporting surfaces (table, ramp, or floor). You will analyze the motion of the block at different moments using the law of conservation of energy.Mastering Physics lists the correct answer at ^''A distance 2h/3 above the floor^'' But why is that the case? Could someone help explain this?Part C If the zero level is a distance 2h/3 above the floor, what is the potential energy U of the block on the floor? Express your answer in terms of some or all the variables m, v, and hand any appropriate constants.Part D Considering that the potential energy of the block at the table is mgh/3 and that on the floor is ?2mgh/3, what is the change in potential energy ?U of the block if it is moved from the table to the floor? Express your answer in terms of some or all the variables m, v, and hand any appropriate constants. Thank you!! Part B Suppose the potential energy of the block at the table is given by mgh/3. This implies that the chosen zero level of potential energy is __________.

Part B

Suppose the potential energy of the block at the table is given by mgh/3. This implies that the chosen zero level of potential energy is __________.


Mastering Physics lists the correct answer at "A distance 2h/3 above the floor"
But why is that the case? Could someone help explain this?

Part C

If the zero level is a distance 2h/3 above the floor, what is the potential energy U of the block on the floor?
Express your answer in terms of some or all the variables m, v, and hand any appropriate constants.

Part D

Considering that the potential energy of the block at the table is mgh/3 and that on the floor is ?2mgh/3, what is the change in potential energy ?U of the block if it is moved from the table to the floor?

Express your answer in terms of some or all the variables m, v, and hand any appropriate constants.

Thank you!!

Answer 1

The diagram for the given situation is shown in the below figure 1n From the law of conservation of energv, we have mgh mghmgh mgh mgh'mgh- 2h Answer a distance 2h/3 above the floor The block has negative potential energy because it is located below the zero level. U--mgh 2h The change in potential energy is obtained as follows 3mgh --mgh