AP Physics 1 S3 HW2

A 45-kg girl is sitting on a seesaw 0.6 m from the balance point, as shown below. How far, on the other side, should a 60-kg boy sit so that the seesaw will remain in balance?

• 0.3 m

• 0.35 m

• 0.4 m

• 0.45 m

A balanced stick is shown below. The distance from the fulcrum is shown for each mass except the 10-g mass. What is the approximate position of the 10-g mass, based on the diagram?

• 7 cm

• 9 cm

• 10 cm

• 15 cm

To weigh a fish, a person hangs a tackle box of mass 3.5

kilograms and a cooler of mass 5 kilograms from the ends

of a uniform rigid pole that is suspended by a rope attached to its center. The system balances when the fish

hangs at a point 1/4 of the rod’s length from the tackle box. What is the mass of the fish?

• 1.5 kg

• 2 kg

• 3 kg

• 6 kg

A meterstick is supported at each side by a spring scale. A heavy mass is then hung on the meterstick so that

the spring scale on the left hand side reads four times the value of the spring scale on the right hand side. If the

mass of the meterstick is negligible compared to the hanging mass, how far from the right hand side is the large

mass hanging.

• 25 cm

• 67 cm

• 76 cm

• 80 cm

A system of two wheels fixed to each other is free to rotate about a frictionless axis through the common center of the wheels and perpendicular to the page. Four forces are exerted tangentially to the rims of the wheels, as shown. The magnitude of the net torque on the system about the axis is

• Zero

• 2FR

• 5FR

• 14FR

A meterstick of negligible mass is placed on a fulcrum at the 0.60 m mark, with a 2.0 kg mass hung at the 0 m

mark and a 1.0 kg mass hung at the 1.0 m mark. The meterstick is released from rest in a horizontal position.

Immediately after release, the magnitude of the net torque on the meterstick about the fulcrum is most nearly

• 2 N.m

• 8 N.m

• 10 N.m

• 16 N.m

For the wheel-and-axle system shown, which of the following expresses the condition required for the system to be in static equilibrium?

• m1 = m2

• am1=bm2

• am2 = bm 1

• a²m1 = b² m2

A uniform meter stick of mass 1 kg is hanging from a thread attached at the stick’s midpoint. One block of mass m = 3 kg hangs from the left end of the stick, and another block, of unknown mass M, hangs

below the 80 cm mark on the meter stick. If the stick remains at rest in the horizontal position shown above, what is M ?

• 4 kg

• 5 kg

• 6 kg

• 8 kg

When you push a door closer to the hinges, why does it open more slowly?

• It opens slowly, because the lever arm is shorter so the torque is large.

• It opens slowly because the lever arm is longer so the torque is large.

• It opens slowly, because the lever arm is shorter so the torque is less.

• It opens slowly, because the lever armIt opens slowly, because the lever arm is shorter so the torque is less.

How can you maximize the torque applied to a given lever arm without applying more force?

• The force should be applied perpendicularly to the lever arm as close as possible from the pivot point.

• The force should be applied perpendicularly to the lever arm as far as possible from the pivot point.

• The force should be applied parallel to the lever arm as far as possible from the pivot point.

• The force should be applied parallel to the lever arm as close as possible from the pivot point.