Question

A certain object is subject to two forces: a 10-N force straight up and a 10-N force straight down. A student states that since both forces are in the vertical direction, the object cannot be moving horizontally. Why is this an incorrect conclusion?

A.
The vertical forces are balanced.
B.
Vertical net forces can cause horizontal motion.
C.
A horizontal force is not required for horizontal movement.
D.
Two vertical forces can combine to form a horizontal resultant force.

Answer 1

C. Consider projectile motion. If an object starts out at some angle and only vertical forces (gravity) are present, the horizontal speed remains constant thruout the motion.