A 4.65 g bullet moving at 824 m/s penetrates a tree to a depth of 5.23 cm. Use energy considerations to find the average frictional force that stops the bullet. Answer in units of N.

30183.92 N

Explanation:

Force: This can be defined as the product of the mass of a body and it's acceleration. The S. I unit of force is Newton (N).

From the question,

The kinetic energy of the bullet = Work done by friction in the tree in stopping the bullet.

1/2mv² = Fₓd ... Equation 1

Where m = mass of the bullet, v = velocity of the bullet, Fₓ = average Frictional force exerted by the tree on the bullet, d = depth of penetration.

Make Fₓ the subject of the equation,

Fx = mv²/2d ... Equation 2

Given: m = 4.65 g = 0.00465 kg, v = 824 m/s, d = 5.23 cm = 0.0523 m.

Substitute into equation 2

Fₓ = 0.00465 (824) ² / (2*0.0523)

Fₓ = 30183.92 N.

Hence the average frictional force = 30183.92 N