Aballet student with her arms and a leg extended spins with an initial rotational speed of 0.90rev/s . as she draws her arms and leg in toward her body, her rotational inertia becomes 0.80 kg⋅m2 and her rotational velocity is 4.1rev/s .
determine her initial rotational inertia.

Amplitude is a measure of a waves a; speed b; distance c; energy d; frequency

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

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.