Question

When an object is moving in a circle, but is not held to the center by a tangible connection like string, what provides the centripital force? a) some force such as gravity or friction b) angle of the surface the object moves on c) natural tendency to move in a circle d) tendency for the object to move in a straight line

Answer 1

Whenever an object moves in a circle, the centripetal acceleration must be provided by some force acting in the direction towards the center of the circle.

For example, the Moon moving around the Earth thanks to the gravitational force, or a marble spining on a cone-shaped surface thanks to the angle of the surface the object moves on.

Notice that option A mentions gravity, but friction always acts in the direction opposite to the movement of an object, so it cannot be responsible for the centripetal acceleration.

Therefore, the answer is:

$\begin{gathered} \text{Option B)} \\ \text{The angle of the surface the object moves on.} \end{gathered}$