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A cue ball (mass 0.17 kg) strikes the eight ball. The cue ball initially moves at 5.0 m/s in the positive x-direction, but is knocked straight back at 4.0 m/s after the collision. What is the average force the eight ball exerts on the cue ball if they are in contact for 0.010 s?

User Aryaxt
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Final answer:

The average force exerted by the eight ball on the cue ball is -153 N during a collision, implying a force of 153 N in the direction opposite to the cue ball's original motion.

Step-by-step explanation:

The student is asking to calculate the average force exerted by the eight ball on the cue ball during a collision in a game of pool. The cue ball has a mass of 0.17 kg, initially moves at 5.0 m/s, and then is knocked back at 4.0 m/s. The time of contact during the collision is 0.010 s.

To find the average force, we use the formula F = \(\frac{\Delta p}{\Delta t}\), where \(\Delta p\) is the change in momentum and \(\Delta t\) is the time over which the change occurs. The change in momentum \(\Delta p\) can be calculated as \(\Delta p = m(v_f - v_i)\), where m is the mass, \(v_i\) is the initial velocity, and \(v_f\) is the final velocity. Substituting the values we have,

\(\Delta p = 0.17 \, kg \, ( -4.0 \, m/s - 5.0 \, m/s ) = -1.53 \, kg\cdot m/s\).

Now, we can calculate the average force,

F = \(\frac{-1.53 \, kg\cdot m/s}{0.010 \, s} = -153 \, N\).

The average force is thus -153 N, which means the eight ball exerts a force of 153 N on the cue ball in the direction opposite to the original motion of the cue ball (since force is a vector and the negative sign indicates direction).

User Steveareeno
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