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.

 

[ogb p]

I understand that these problems may seem difficult and overwhelming at first, but with some guidance and practice, they can be solved. Here are some tips that may help you tackle these problems:

1. Start by drawing a diagram and labeling all the given information. This will help you visualize the problem and identify any unknown variables.

2. Identify the physical principles involved in the problem. In the first two problems, the principle of conservation of momentum and the principle of conservation of kinetic energy are relevant. In the third problem, the principle of conservation of momentum and the Hooke's Law are important.

3. Use the given equations and principles to set up equations that relate the initial and final states of the system. In the first two problems, you can use the equations for conservation of momentum and kinetic energy. In the third problem, you can use the equation for conservation of momentum and the Hooke's Law equation.

4. Solve for the unknown variables by substituting the given values into the equations. Make sure to pay attention to units and use the appropriate units for each variable.

5. Check your answer by making sure it makes sense and is consistent with the principles and equations used in the problem.

If you are still having trouble, I recommend seeking help from a physics tutor or your instructor. They can provide you with additional guidance and practice problems to improve your understanding. Remember, with patience and practice, you can solve these "impossible" physics problems. Good luck!