AP Physics 1 Free Response Question Answers for Momentum
π Welcome to the AP Physics Unit 5 FRQ (Momentum) Answers. Have your responses handy as you go through the rubrics to see how you did!
β± Remember, the AP Physics 1 exam has 5 free-response questions, and you will be given 90 minutes to complete the FRQ section. (This means you should give yourself ~18 minutes to go through each practice FRQ.)
Setup
Identical blocks 1 and 2 are placed on a horizontal surface at points A and E, respectively, as shown. The surface is frictionless except for the region between points B and C, where the surface is rough. Beginning at time tA, Block 1 is pushed with a constant horizontal force from Point A to Point B by a mechanical plunger.
Upon reaching Point B, Block 1 loses contact with the plunger and continues moving to the right along the horizontal surface toward Block 2. Block 1 collides with and sticks to Block 2 at Point E, after which the two-block system continues moving across the surface, eventually passing Point F.
Questions with Answers & Rubric
Part A
(i) On the axes below, sketch the speed of the center of mass of the two-block system as a function of time, from time tA until the blocks pass Point F at time tF. The times at which Block 1 reaches Points A through F are indicated on the time axis. (3pts)
Part B
The system is reset and Block 1 is again released. The following conditions now exist:
Mass of Block 1 (kg)
Mass of Block 2 (kg)
Spring Constant (N/m)
Distance Between Each Letter
Coefficient of Friction, Β΅
5
3
825
1.2
0.15
In addition, there is no friction on the horizontal surface except for between letters B and C.
(i) Determine the speed of Block 1 at Point B. (3pts)