Review Warm Up

If the torque required to loosen a nut on the wheel of a car has a magnitude of 60.0 N• m, what minimum perpendicular force must be exerted by a mechanic at the end of a 45.0 cm wrench to loosen the nut?

• 0.666 Nm
•  133.3 N
• 66.7 N
• 13.3 Nm

A state of equilibrium is also seen below. Each of the cars weighs the same  9800 N. Despite the fact that there is only one car on the left-hand side that is 9 m from the fulcrum, the torques balance because, the car on the left-hand side, is ____meters from the fulcrum, compared to the cars on the right-hand side.

• 4.5 m
• 3 m
• 1 m
• 2 m

Find the magnitude of the torque produced by a 5.0 N force applied to a door at a perpendicular distance of 65 cm from the hinge.

• 75 Nm
• 3.25 Nm
• 6.3 Nm
• 8.75 Nm

You apply force to a wrench to tighten a bolt. The wrench breaks in half. Select the best answer for what happens next. Assume the force applied remains constant.

• The torque is now half of what it was, because torque and distance are inversely proportional
• The torque is now half of what it was, because torque and distance are directly proportional
• The torque is now double of what it was, because torque and distance are inversely proportional
• The torque is now double of what it was, because torque and distance are directly proportional

A seesaw is unbalanced with two people of different masses sitting equal distances from the center. Which of the following will result in equilibrium?

• The larger person moving further away from the center.
• Moving the smaller person closer to the center.
• Moving the smaller person further from the center.
• Making the larger person do nothing.

A wrench is used to tighten a nut. A 15N perpendicular force is applied 50cm away from the axis of rotation, and moves a distance of 10 cm as it turns. What is the torque applied to the wrench?

• 7.5 Nm
• 1.5 Nm
• 750 Nm
• 150 Nm

The easiest way to open a heavy door  is by applying the force

• Near the hinges
• In the middle of the door
• At the edge of the door far from the hinges
• At the top of the door

In the diagram above, two masses, one with mass m, the other with mass M = 2m are resting on a uniform plank of length L that pivots at its midpoint. If the mass m is at the far end of the plank, how far away from the pivot should the mass M be to balance the plank in a horizontal position shown?

• L/2
• L/3
• L/4
• L/6

When an object is experiencing a net torque

• it is in dynamic equilibrium.
• it is in static equilibrium.
• it is rotating.
• it is translating.

An airplane accelerates down a runway from rest at 3.20 m/s² for 32.8 s until is finally lifts off the ground. Determine the distance traveled before takeoff.

Which equation is appropriate?

• vf=vi+a*t

• x=vi*t+1/2at²

• vf²=vi²+2aX

• x=((vf+vi)/2)t