As you push a cereal box across a tabletop, the sliding friction acting on the cereal a.) acts in the direction of motion. b.) equals the weight of the box. c.) is usually greater than static friction. d.) acts in the direction opposite of motion. 2.) projectile motion is caused a.) the downward force of gravity. b.) the initial forward velocity. c.) a final vertical velocity d.) the downward force of gravity and an initial forward velocity.

1: d) acts in the direction opposite of motion

Explanation:

Sliding friction is a force that is exerted when an object is sliding along a surface. Due to the surfaces are never perfectly smooth, the collisions between the molecules at the edges of the object and the surface "slow down" the motion of the object. Because of this, sliding friction acts in the direction opposite of motion.

2: d.) the downward force of gravity and an initial forward velocity.

A projectile motion is a motion that consists of two independent motions:

- A horizontal motion at constant velocity

- A vertical accelerated motion with constant acceleration (g, gravitational acceleration, due to the force of gravity which acts downwards)

Therefore, projectile motion is caused by the downward force of gravity and an initial forward velocity.