Unit 7: Torque and Rotational Dynamics

Torque is calculated as:

A 0.5 m long wrench applies a force of 80 N perpendicular to its handle. What is the torque in N·m?

A force of 20 N is applied perpendicular to a wrench at a distance of 0.3 m from the bolt. The torque is

A uniform beam of mass 10 kg and length 4 m is supported at one end. What force must be applied at the other end to keep it horizontal? (g = 10 m/s²)

A solid sphere and a solid cylinder of the same mass and radius start from rest at the top of an incline. Which has larger translational velocity at the bottom?

For an object to be in static equilibrium, which conditions must be met?

A net torque of 12 N·m acts on an object with moment of inertia 3 kg·m². The angular acceleration is

The rotational kinetic energy of a wheel spinning at angular velocity ω with moment of inertia I is

A 4 m uniform plank of mass 20 kg rests on two supports: one at the left end and one at 3 m from the left. A 60 kg person stands at the right end. The force on the left support is (g = 10 m/s²)

When opening a door, pushing farther from the hinge requires less force because

A child weighing 300 N sits 2 m from the pivot of a seesaw. Where must a child weighing 200 N sit to balance?

Two solid cylinders of the same mass roll down an incline. Cylinder A has a larger radius than Cylinder B. Which reaches the bottom first?

A figure skater brings her arms in during a spin. What happens?

The lever arm is:

A solid sphere, a solid cylinder, and a hollow sphere of equal mass and radius roll down the same incline from rest. Which reaches the bottom first?

Two objects (3 kg at x = 2 m and 1 kg at x = 6 m) form a system. Where is the center of mass?

Why is a door handle placed far from the hinges?

A ball rolling without slipping has total kinetic energy equal to:

Angular momentum is conserved when:

A 40 N force is applied at 30° to a wrench 0.5 m from the bolt. What is the torque?

Moment of inertia is the rotational equivalent of:

A beam is in static equilibrium. This means:

What is the net torque about the pivot?

What force must the support at B exert to maintain equilibrium?

What is the angular acceleration of the disk?

What is the torque produced by the force about the pivot?

What is the total moment of inertia of the system about the axis?

How long does it take the wheel to stop?

Where should a 60 kg person sit to balance the seesaw?

What is the acceleration of the hanging mass?

How much work is done by the torque?

What is the minimum coefficient of static friction needed at the floor?

A uniform beam of length 4.0 m and mass 20 kg is supported at its center. A 10 kg mass is placed 1.5 m from the left end. Where must a 15 kg mass be placed on the right side of the center to balance the beam? (g = 10 m/s²)

A door of width 1.0 m is pushed with a force of 40 N. If the force is applied at the edge (1.0 m from hinges) vs at the center (0.50 m from hinges), by what factor does the torque differ?

A uniform 4 m beam (mass 20 kg) is supported at two points: one at the left end and one at 3 m from the left end. A 30 kg mass hangs from the right end. What is the force at the left support? (g = 10 m/s²)