# Impossible AP Physics Problems

1. Dec 5, 2007

### mrbetty16

I need help with some of these problems. Any kind of help will be most appreciated

1. Speed amplifier. In Fig. 10-3, block 1 of mass m1 slides along an x axis on a frictionless floor with a speed of v1i = 2.80 m/s. Then it undergoes a one-dimensional elastic collision with stationary block 2 of mass m2 = 0.200m1. Next, block 2 undergoes a one-dimensional elastic collision with stationary block 3 of mass m3 = 0.200m2

2. Speed deamplifier. In Fig. 10-5, block 1 of mass m1 slides along an x axis on a frictionless floor with a speed of 2.40 m/s. Then it undergoes a one-dimensional elastic collision with stationary block 2 of mass m2 = 2.70m1. Next, block 2 undergoes a one-dimensional elastic collision with stationary block 3 of mass m3 = 2.70m2.

3. A block of mass m1 = 2.2 kg slides along a frictionless table with a speed of 8 m/s. Directly in front of it, and moving in the same direction, is a block of mass m2 = 5.0 kg moving at 2.8 m/s. A massless spring with spring constant k = 1100 N/m is attached to the near side of m2, as shown in Fig. 10-35. When the blocks collide, what is the maximum compression of the spring? (Hint: At the moment of maximum compression of the spring, the two blocks move as one. Find the velocity by noting that the collision is completely inelastic to this point.)

2. Dec 6, 2007

### silver-rose

1) Employ the idea of the conservation of momentum for the first problem:

$$m_{1}u_{1} + m_{2}u{2}=m_{1}v_{1} + m_{2}v{2}$$ where u is the velocity before collision and v, the velocity after collision. Express all the masses in terms of m1.

2) I don't see how the 2nd problem differs from the first in terms of technique and theory.

3) Energy of the two blocks moving as one (ie inelastic collision) = Energy used to compress spring.