Question

which of the following is an example of a contact force? (1 point)
○ a person standing perfectly still on the ground
○ a magnet pulling a screw toward it
○ rain falling from the sky
○ a skydiver in freefall

Explanation:

• A contact force requires physical contact between two objects.
• When a person stands on the ground, there is physical contact between the person and the ground. The ground exerts a normal force (a contact force) on the person to support them.
• A magnet pulling a screw is a non - contact force (magnetic force).
• Rain falling is due to gravity (a non - contact force).
• A skydiver in freefall is mainly affected by gravity (non - contact force) and air resistance (but in freefall, the dominant force initially is gravity, a non - contact force).

Answer:

a person standing perfectly still on the ground