Question

Lucia wants to change the motion map shown so that it shows uniform circular motion.

An illustration of a circle with four black dots on the top, bottom, left and right of the circle. Each dot has a vector toward the center of the circle and a vector tangent to the circle in a counterclockwise direction.
What change should Lucia make?

She should change the length of each vector that is tangent to the circle so that it is the same as the vector pointing toward the center at that point.
She should change the direction of the vectors that are toward the center of the circle so that each points tangent to the circle opposite the existing tangent vectors.
She should change the direction of the vectors that are toward the center of the circle so that each points away from the center of the circle.
She should change the lengths of the vectors that point toward the center so that each is the same length.

Answer 1

She should change the lengths of the vectors that point toward the center so that each is the same length.

Reason: uniform circular motion has constant speed and a constant-magnitude centripetal acceleration directed inward, so the inward (radial) acceleration arrows must all be equal in length.