A tether ball is attached to the top of a vertical pole by a string. The tether ball moves in a circle in the horizontal plane. The string sweeps out the surface of a right circular cone, with the apex of the cone at the top where the string is attached to the top of the pole. Which of the following causes the tether ball to move with uniform circular motion? a. Gravitational force b. Tension in the string c. Vertical component of the tension in the string d. Horizontal component of the tension in the string

d)

Explanation:

The horizontal component of the tension in the string is what causes the tether ball to move with uniform circular motion since this circle is in the horizontal plane and thus the centripetal acceleration of the ball must be also in it, pointing towards the center of the circle. The vertical component of the tension in the string cancels out the gravitational force.

for this one it would be d bump/forearm pass

layer a is the exosphere and layer b is the thermosphere.   is the answer i think but i hope this .