A 37 g bullet pierces a sand bag 15cm thick. If the initial bullet velocity was 66 m/s and it emerged from the sandbag with 32 m/s, what is the magnitude of the friction force (assuming it to be constant) the bullet experienced while it traveled through the bag

Ff = 410.94 N

Explanation:

In order to calculate the friction force that the bullet experiences while it travels trough the bag, you take into account that the work done by the friction force in the bag, is equal to the change in the kinetic energy of the bullet. You use the following formula:

       (1)

Wb: work done by the friction force

Ff: friction force = ?

d: thick of the sand bag = 15cm = 0.15m

m: mass of  the bullet  = 37g = 37*10^-3 kg

v: bullet's speed after it go out from the sand bag = 32m/s

vo: bullet's speed before it enter to the sand bag = 66m/s

You solve the equation (1) or Ff, and replace the values of the other parameters:

The minus sign means that the friction force is against the direction of the motion of the bullet.

The magnitude of the friction force is 410.94 N

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.