Impulse Physics Example 2

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Example 2

medium
A 0.15 kg0.15 \text{ kg} baseball moving at 40 m/s40 \text{ m/s} is hit by a bat and reverses direction at 50 m/s50 \text{ m/s}. What impulse did the bat deliver?

Solution

  1. 1
    Define the initial direction as positive. Initial momentum: pi=0.15×40=6 kg m/sp_i = 0.15 \times 40 = 6 \text{ kg m/s}.
  2. 2
    Final momentum (reversed): pf=0.15×(−50)=−7.5 kg m/sp_f = 0.15 \times (-50) = -7.5 \text{ kg m/s}.
  3. 3
    Impulse equals change in momentum: J=pf−pi=−7.5−6=−13.5 N sJ = p_f - p_i = -7.5 - 6 = -13.5 \text{ N s}
  4. 4
    The magnitude of the impulse is 13.5 N s13.5 \text{ N s}.

Answer

J=13.5 N sJ = 13.5 \text{ N s}
When an object reverses direction, the change in momentum is especially large because you must account for stopping the original motion and creating motion in the opposite direction.

About Impulse

The product of force and time interval, equal to the resulting change in an object's momentum.

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More Impulse Examples

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A force of [formula] acts on a ball for [formula]. What is the impulse delivered to the ball?

Example 3 medium

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Example 4 medium

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