Which situation shows a non-contact force changing the speed of an object?

Question

1. Raking a leaf
2. A person riding a bike and moving the pedals faster
3. A nail rolls off the edge of a roof and falls to the ground
4. A batter hitting a baseball

Answer 1

The situation that shows a non-contact force changing the speed of an object is:

3. A nail rolls off the edge of a roof and falls to the ground.

In this case, the nail is affected by gravity, which is a non-contact force. Gravity pulls the nail downwards, changing its speed as it falls. The other situations involve contact forces: raking a leaf, pedaling a bike faster, and hitting a baseball all require physical contact to exert force.