# Average force exerted by the ball

## Homework Statement

A baseball (m = 145 g) traveling 35 m/s moves a fielder's glove backward 15 cm when the ball is caught. What was the average force exerted by the ball on the glove?
Magnitude

-(1/2)mv^2

## The Attempt at a Solution

(1/2)(145)(35)^2=-88812.5

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PhanthomJay
Homework Helper
Gold Member
you have calculated the kinetic energy lost. The problem asks for the force. What equation(s) might you use to solve for F?

F=(1/2)kx^2

Be careful with your calculations - baseball m = 145 g ...

PhanthomJay
Homework Helper
Gold Member
F=(1/2)kx^2
No, you're fishing in the wrong pool! Are you familiar with energy methods, or kinematics and Newton 2?

would the equation just be F=mv?

PhanthomJay
Homework Helper
Gold Member
would the equation just be F=mv?
You mean F=ma, don't you? So how would you calculate 'a' knowing that the ball goes from 35m/s to a stop in a 15cm distance? (Hint: use the kinematic equation that relates distance with acceleration and velocity change, and watch your units.

Vf^2=Vi^2*a*d

0=1225+2*a*.15
-2*a*.15=1225
a*.15=-612
a=-4083.3

PhanthomJay