Question

Which of the following is true about a planet orbiting a star in uniform circular motion?

A. The direction of the velocity vector is always changing.
B. The velocity of the planet is constant.
C. The speed of the planet is always changing.
D. The acceleration vector of the planet points directly away from the star.

Answer 1

as it is uniform circular motion therefore speed is constant , therefore we can rule out option B, also in circular motion the direction of velocity vector changes therefore Velocity cant be constant therefore Option B is incorrect as well. Also centripetal acceleration is always towards the center so Option D is wrong as well.
That Implies
Option A is correct :)