Need Help with These AP Physics Problems?

[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.)

 

[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.