A tennis ball of mass m = 0.065 kg and speed v = 25 m/s strikes a wall at a 45° angle and rebounds with the same speed at 45° (Fig. 7-29). What is the impulse given the wall?

I started out with finding the momentum and doubling it to get the impulse on the wall but that isn't the right answer. What equation do I need to start this one? Does it have to do with the angles they are giving me?

No, that is not right. Only the normal component doubles.

Vfinalnormal =25*.707*2

Force*time=m*vfinalnormal
You have to only dealt with what changed, the momentum normal, and the implulse norma.

To find the impulse given to the wall, you need to consider the conservation of momentum. Let's break down the problem step by step:

1. Determine the initial momentum of the tennis ball before it strikes the wall.
- The momentum of an object is defined as the product of its mass and velocity.
- In this case, the mass of the tennis ball is given as m = 0.065 kg, and its speed is v = 25 m/s.
- Therefore, the initial momentum of the ball is p_initial = m*v.

2. Analyze the collision with the wall:
- The ball strikes the wall at a 45° angle and rebounds with the same speed at a 45° angle.
- When a ball collides with a wall, it experiences a change in momentum due to the wall exerting an impulse on it.
- The impulse is determined by the change in momentum.

3. Determine the final momentum of the tennis ball after it rebounds.
- Since the ball rebounds with the same speed and at the same angle, its final momentum will be equal in magnitude but opposite in direction to the initial momentum.
- Thus, the final momentum of the ball, p_final, is equal to -p_initial.

4. Calculate the change in momentum (Δp).
- The change in momentum is given by the final momentum minus the initial momentum.
- Δp = p_final - p_initial.

5. Calculate the impulse given to the wall.
- Impulse is the change in momentum experienced by an object.
- Impulse = Δp = p_final - p_initial.

Now that we've determined the necessary steps, let's calculate the impulse given to the wall:
- The initial momentum, p_initial = m*v = 0.065 kg * 25 m/s = 1.625 kg·m/s.
- The final momentum, p_final = -p_initial = -1.625 kg·m/s.

Impulse = Δp = p_final - p_initial = (-1.625 kg·m/s) - (1.625 kg·m/s) = -3.25 kg·m/s.

Therefore, the impulse given to the wall is -3.25 kg·m/s. Note the negative sign indicates a change in direction of momentum.