Moderate

A cricket ball of mass 0.5 kg strikes a bat normally with a velocity of 30 m s-1 and rebounds with a velocity of 20 ms-1 in the opposite direction. The impulse of the force exerted by the ball on the bat is

Correct answer: B. 25 N s

  • A. 0.5 N s
  • B. 25 N s
  • C. 1.0 N s
  • D. 50 N s

Explanation

Impulse is defined as the change in momentum of an object. For this problem, you calculate the impulse by finding the change in velocity before and after the collision. The formula is I = m(u + v), where u is the initial velocity (30 m/s) and v is the velocity after rebound (20 m/s, in the opposite direction so it becomes positive when summed). Therefore, I = 0.5 kg * (30 m/s + 20 m/s) = 25 N s. The other options do not correctly apply the concept of impulse, which is why their calculations are incorrect.

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About Force and Motion

Displacement, velocity and acceleration describe motion, including the horizontal and vertical components of projectile motion. The chapter connects these quantities with Newton's laws, momentum and impulse, then applies conservation of momentum to collisions, distinguishing elastic collisions from inelastic ones.

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