Physics
posted by Dani .
A 7.80g bullet moving at 530 m/s penetrates a tree trunk to a depth of 6.2 cm.
(a) Use work and energy considerations to find the average frictional force that stops the bullet.
(b) Assuming the friction force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment it stops moving

change in KE =1/2mv^2
1/2(.0078)(530)^2=1095.51 kg*m^2/s^2
6.2 cm = .0062 m
1095.51/.0062 = 176,695 N= F
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