At the starting gun a runner accelerates from rest at 3.1 m/s2 for 2.9 s. What is the runner's speed 2 s after she starts running?

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Suppose you have a box. which of these is not necessarily a true statement regarding the relationship between the force applied to the box, the work done on the box, and the distance the box is moved? a. if the box is not moved, no force is being applied to the box. b. if no force is applied to the box, no work is done on the box. c. if work is done on the box, then a force is applied to the box. d. if work is done on the box, then the box is moved a distance.