A 0.24 kg blob of clay is thrown at a wall with an initial horizontal velocity of $16 \mathrm {~m} / \mathrm { s }$ If the clay comes to a stop in $91 \mathrm {~ms} \text {, }$ what is the average horizontal force exerted on the clay by the wall?
A)42 N
B)26 N
C)35 N
D)51 N

Question

Quizplus · Accepted Answer

The average force is equal to the change in momentum divided by the time interval. The change in momentum is equal to the final momentum minus the initial momentum. The final momentum is zero, so the change in momentum is equal to the initial momentum. The initial momentum is equal to the mass times the initial velocity. The time interval is equal to the time it takes for the clay to come to a stop. Therefore, the average force is equal to the mass times the initial velocity divided by the time it takes for the clay to come to a stop. Plugging in the given values, we get:$$F = \frac{mv}{t} = \frac{(0.24 	ext{ kg})(16 	ext{ m/s})}{0.091 	ext{ s}} = 42 	ext{ N}$$

A 024 Kg Blob of Clay Is Thrown at a Wall