**Kinetics, the study of unbalanced forces causing motion, can be analyzed by three methods: inertia force or torque (dynamic equilibrium), work and energy, and impulse and momentum.**

**Consider the following as you complete your assignment:**

**For linear motion the inertia force is**

**Equal to ma**

**Acting through the center of gravity**

**Opposite in direction to the acceleration **

**For rotational motion the inertia torque is**

**Equal to C**

**Opposite in direction to the angular acceleration **

**For a plane motion problem such as a rolling cylinder, try to**

**Equate or relate linear acceleration to angular acceleration.**

**Take moments at the rolling point of contact with the surface.**

**Questions**

13–1.

Determine the acceleration of the 150-lb block in Figure P13–1 if the coefficient of kinetic friction is 0.4.

13–3.

A 130-kg cart is accelerated horizontally by a 250-N force pulling at an angle of 20° above horizontal. Neglecting rolling resistance, determine the acceleration of the cart.

13–7.

At what maximum acceleration rate can a 500-N test-strength cable lift a 40-kg mass?

13–8.

What force does a 180-lb man exert on the floor of an elevator that is moving downward and decelerating at 15 ft/s^2?

13–20.

The coefficient of kinetic friction for mass B in Figure P13–20 is 0.25. Determine the acceleration of mass A if it has a mass of (a) 30 kg and (b) 50 kg.

13–36.

A 1000-kW generator has a 3500-lb rotor that is accelerated from rest to 3600 rpm in 10 seconds. Determine the torque required. Assume the rotor to be a solid cylinder 40 in. in diameter.

13–41.

A 150-mm-diameter shaft with a mass of 20 kg is rotating at 900 rpm. A pulley mounted on the shaft has a mass moment of inertia of 0.15 kg ⋅ m^2. If the shaft and the pulley coast to a stop due to a tangential frictional force of 8 lb at the outer radius of the shaft, determine the time required.