Conservation of Energy AP Physics 1 FRQ – Exam Style Questions etc.
Conservation of Energy AP Physics 1 FRQ
Unit: 3. Work , Energy and Power
Weightage : 10-15%
Exam Style Practice Questions, Conservation of Energy AP Physics 1 FRQ
Question: (7 points, suggested time 13 minutes)
A physics class is asked to design a low-friction slide that will launch a block horizontally from the top of a lab table. Teams 1 and 2 assemble the slides shown above and use identical blocks 1 and 2, respectively. Both slides start at the same height d above the tabletop. However, team 2’s table is lower than team 1’s table. To compensate for the lower table, team 2 constructs the right end of the slide to rise above the tabletop so that the block leaves the slide horizontally at the same height h above the floor as does team 1’s block (see figure above).
(a) Both blocks are released from rest at the top of their respective slides. Do block 1 and block 2 land the same distance from their respective tables?
____ Yes ____ No
Justify your answer.
In another experiment, teams 1 and 2 use tables and low-friction slides with the same height. However, the two slides have different shapes, as shown below.
(b) Both blocks are released from rest at the top of their respective slides at the same time.
i. Which block, if either, lands farther from its respective table?
____ Block 1 ____ Block 2 ____ The two blocks land the same distance from their respective tables.
Briefly explain your reasoning without manipulating equations.
ii. Which block, if either, hits the floor first?
____ Block 1 ____ Block 2 ____ The two blocks hit the floor at the same time.
Briefly explain your reasoning without manipulating equations.
▶️Answer/Explanation
Ans:
√ No
For team I, all of the block’s potential energy, gets converted into kinetic energy. This is also true for team 2, However with team 2, the block has less initial potential energy than team t, b/c it travels a shorter not vertical distance to therefore it has less kinetic energy at height h. This results in less velocity at height h for team so a shorter distance travelled b/c both blocks are in the air for the same amount of time.
(b)
i. √ The two blocks land the same distance from their respective tables.
Even though the slides have different heights, the changes in height are the same so they have the same potential energy at the start, and kinetic energy at the and, since they launch from the same height h, they are in the air for the same amount of time and go the same distance.
ii. √ Block 1
Block 1 travels a shorter horizontal distance on the table before reaching its maximum speed than block 2. This means it reaches the end of the table before block 2 and hits the ground first because they are in the air for the same amount of time.