Question

7. A ball of mass 0.1 kg moving at 10 m s' is deflected by a wall at the same
speed in the direction shown. What is the magnitude of the change in
momentum of the ball?
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Answer 1

Answer: 2

Explanation: momentum=mv

change in momentum = final momentum - initial momentum

first of all we are taking initial direction positive so,

Initial Momentum = m(v)= 1 kg m/sec

final momentum = m(-v)= -1 kg m/sec

so change in momentum = (-1)-(1) kg m/sec = -2 kgm/sec

so answer is 2