002 10.0 points A figure skater begins spinning counterclock-
wise at an angular speed of 4.0 rad/s. Dur-
ing a 4.1 s interval, she slowly pulls her arms
inward and finally spins at 7.0 7 rad/s.
What is her average angular acceleration
during this time interval?
Answer in units of rad/s2.

Find the momentum for a 2.6-kg brick parachuting straight downward at a constant speed of 8.4 m/s .

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.

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.