A racquet ball with mass m = 0.254 kg is moving toward the wall at v = 18.8 m/s and at an angle of θ = 27° wit?
What is the magnitude of the initial momentum of the racquet ball?
What is the magnitude of the change in momentum of the racquet ball?
What is the magnitude of the average force the wall exerts on the racquet ball?
Now the racquet ball is moving straight toward the wall at a velocity of vi = 18.8 m/s. The ball makes an inelastic collision with the solid wall and leaves the wall in the opposite direction at vf = -11.8 m/s. The ball exerts the same average force on the ball as before.
What is the magnitude of the change in momentum of the racquet ball?
What is the time the ball is in contact with the wall?
What is the change in kinetic energy of the racquet ball?
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I'll assume that the question ends "with respect to the perpendicular". If it is w/r/t the wall, then you'll have to swap sines and cosines.
p_initial = 0.254kg * 18.8m/s = 4.78 kg·m/s
p_xi = 4.78kg·m/s * cos27º = 4.25 kg·m/s, and this gets reversed (assumed), so the magnitude of the change in momentum is -8.51 kg·m/s
Average force cannot be determined without the duration of the impact. If you have that, divide it into the change in momentum above; the force exerted by the wall is negative (against the direction of motion, assumed positive).
Now, Δp = (-11.8 - 18.8)m/s * 0.254kg = 7.77 kg·m/s
Divide this from the force above to get the duration of impact, Δt.
ΔKE = ½ * 0.254kg * (11.8² - 18.8²)m²/s² = -27.2 J