A 0.5 kg ball moving with a speed of 12 m/s strikes a hard wall at an angle of 30° with the wall. It is reflected with the same speed and at the same angle. If the ball is in contact with the wall for 0.25 s, the average force acting on the wall is :

Question

Dr. Abubacker · Accepted Answer

[Solution from source] The ball meets the wall at 30° to the wall, so its velocity component normal to the wall is 12 sin 30° = 6 m/s; this component reverses while the parallel component is unchanged. Δp = 2 × 0.5 × 6 = 6 kg m/s and F = 6/0.25 = 24 N. Using cos 30° (treating the angle as measured from the normal) gives about 41.6 N, which is not offered. Answer (2).

Q. A 0.5 kg ball moving with a speed of 12 m/s strikes a hard wall at an angle of 30° with the wall. It is reflected with the same speed and at the same angle. If the ball is in contact with the wall for 0.25 s, the average force acting on the wall is :

Explanation

Reviewed by Dr. Abubacker

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