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# Physics help with a problem needed bad?

Please show all your work, answer in correct SI format, and round to 2 decimal places.

A baseball with a mass of 0.2 kg is pitched at a velocity of 40m/s toward a batter. The batter hits the ball directly back towards the pitcher at 65 m/s. Please remember that opposing directions cannot both have "positive" qualifiers.

a. What is the impulse of the ball?

B. What force must be exerted if the contact time is 0.003 s?

c. How would the force change if the contact time was only 0.001 s?

### 1 Answer

- sojsailLv 78 years agoFavorite Answer
a. The impulse on the ball equals the ball's change in momentum. Let the ball's original velocity be positive.

Delta momentum = m*Vf - m*Vi = 0.2 kg*(-65 m/s) -0.2 s*40 m/s = ____ kg.m/s

b. Impulse has a second definition.

Impulse = force*time of duration of the force

Plug in impulse from part a, plug in the time of contact, and solve for the force.

Note: 1 kg.m/s^2 = 1 N

c. Repeat part b with the new time to find out.