Can a set of forces have a net torque that is zero and a net force that is not zero?

Check your Understanding Repeat Example 12.3 using the left end of the meter stick to calculate the torques; that is by placing the pivot at the left end of the meter stick.

If the torque acting on a particle about an axis through a certain origin is zero, what can you say about its angular momentum about that axis?

An automobile engine can produce 200Nm of torque. Calculate the angular acceleration produced if 95.0 of this torque is applied to the drive shaft, axle, and rear wheels of a car, given the following information. The car is suspended so that the wheels can turn freely. Each wheel acts like a 15.0-kg disk that has a 0.180-m radius. The walls of each tire act like a 2.00-kg annular ring that has inside radius of 0.180 m and outside radius of 0.320 m. The tread of each tire acts like a 10.0-kg hoop of radius 0.330 m. The 14.0-kg axle acts like a rod that has a 2.00-cm radius. The 30.0-kg drive shaft acts like a rod that has a 3.20-cm radius.

Repeat Example 10.15 in which the stick is free to have translational motion as well as rotational motion.

(a) A solid cylinder of mass 1.50 kg and radius 55.0 cm has a net torque of magnitude 0.170 N-m about the axis through its center. Determine the magnitude of its angular acceleration.

(I) A 52-kg person riding a bike puts all her weight on eachpedal when climbing a hill. The pedals rotate in a circle ofradius 17 cm. (a) What is the maximum torque she exerts?(b) How could she exert more torque?

(II) A person exerts a horizontal force of 42 N on the end of a door 96 cm wide. What is the magnitude of the torque if the force is exerted (a) perpendicular to the door and (b) at a 60.0° angle to the face of the door?

A uniform rod of mass M and length l can pivot freely (i.e., we ignore friction) about a hinge attached to a wall, as in Fig. 8-63. The rod is held horizontally and then released. At the moment of release, determine (a) the angular acceleration of the rod, and (b) the linear acceleration of the tip of the rod. Assume that the force of gravity acts at the center of mass of the rod, as shown. [Hint: See Fig. 8–20g.] СМ FIGURE 8-63 Problem 89. Mỹ