A bullet of mass 20 g strickes a fixed block of wood at a speed of 320m/s. The embeds itself into the block of wood, penetrating to a depth of 6.0cm. Calculate the average net force acting on the bullet while it is being brought to rest.
What is the force of the bullet? By your reasoning, the average force = initial force/2. Why would that be? You seem to be mixing up average velocity with average force.The block will stop all of the force applied by the bullet; when it just enters the block, the force is equal to that of the force of the bullet, when it stops there is no force. So the average force would be the average of those two forces.