Question

A rock is thrown straight up. What is the net external force acting on the rock when it is at the top of its trajectory?

a) The net external force is zero.

b) The net external force is upward.

c) The net external force is downward.

d) The net external force is constant.

Answer 1

When a rock is thrown straight up and reaches the top of its trajectory, the net external force acting on the rock is downward due to the force of gravity.

Step-by-step explanation:

When a rock is thrown straight up and reaches the top of its trajectory, the net external force acting on the rock is downward. This means that the answer is c) The net external force is downward.

The force of gravity is the main external force acting on the rock, causing it to accelerate downward. At the top of its trajectory, the rock momentarily comes to rest before changing direction and accelerating downward due to the force of gravity.