Torque
A torque acting on an object tends to produce:
A) Equilibrium D) Velocity
B) Rotation E) A center of gravity
C) Linear Motion
B) Rotation
On a balanced see saw, a boy three times as heavy as his partner sits:
a) 1/3 the distance from the fulcrum
b) less than 1/3 the distance from the fulcrum
c) more than 1/3 the distance from the fulcrum
a) 1/3 the distance from the fulcrum
When doing somersaults, you'll more easily rotate when your body is:
a) Straight
b) Balled up
c) No difference
b) Balled up
Horses that move with the fastest linear speed on a merry-go-round are located:
a) near the center
b) near the outside
c) anywhere because they all move at the same speed
b) near the outside
Where should a force be applied on a lever arm to produce the most torque?
a) closest to the axis of rotation
b) farthest from the axis of rotation
c) in the middle of the lever arm
d) it doesn't matter where the force is applied
b) farthest from the axis of rotation
True or false:
A moving object is not in equilibrium.
False. An object can be moving or rotating at a constant rate and it would be in equilibrium.
Which of the following represents Newton's second law for rotating objects?
a) net torque=moment of inertia * angular acceleration
b) net torque=moment of inertia / angular acceleration
c) force = mass *acceleration
d) force = mass / acceleration
a) net torque = moment of inertia * angular acceleration
Show the conversion from degrees to radians.
# degrees * (2*Pi rads/360 degrees) = # rads
To turn a stubborn screw, it is best to use a screwdriver that has a:
a) Wide handle
b) Long handle
c) Yellow color
) None of these
a) Wide handle
For a system in mechanical equilibrium, the net force on the system:
a) is zero
b) and the net torque on the system are zero
c) may be any amount as long as the net torque is zero
b) and the net torque on the system are zero
Stand a meter stick on its end and let go and it rotates to the floor. If you attach a heavy weight to its upper end and repeat, falling time will be:
a) more
b) less
c) the same
a) more
A car travels in a circle with constant speed. The net force on the car is:
a) directed forward, in the direction of travel
b) directed towards the center of the curve
c) zero because the car is not accelerating
d) none of these
b) directed towards the center of the curve
Put a pipe over the end of a wrench when trying to turn a stubborn nut on a bolt, to effectively make the wrench handle twice as long, you'll increase the torque by
a) two
b) four
c) eight
a) two
Which of the following statements is correct?
a) with a net positive torque, the angular acceleration of an object is clockwise
b) with a net positive torque, the angular acceleration of an object is counterclockwise
c) with a net negative torque, the angular acceleration of an object is counterclockwise
d) the net force of an object is not related to the translational acceleration given to the object
b) with a net positive torque, the angular accleration of an object is counterclockwise
Which will roll faster down a hill; an empty car tire or the same tired mounted on a rim?
a) the mounted tire if the tire is heavier than the rim
b) the mounted tire if the tire is not as heavy as the rim
c) the empty tire regardless of its weight
d) the empty tire if it is as heavy as the rim
e) the empty tire regardless of its weight
c) the mounted tire regardless of its weight
Suppose you put very large-diameter tires on your car. Then, your speedometer will show a speed that is
a) higher than it actually is
b) lower than it actually is
b) lower than it actually is
To warm up before a game, a baseball pitcher tosses a 0.15 kg ball by rotating his forearm, which is 0.32 m in length, to accelerate the ball. The ball starts at rest and is thrown at a speed of 12 m/s in 0.4 s.
While the ball is in the pitcher's hand, what torque is applied to the ball to produce the angular acceleration?
1.4 N*m
A uniform bridge span weighs 50,000 N and is 40.0 m long. An automobile weighing 15,000 N is parked with its center of gravity located 12.0 m from the right pier.
What upward support force is provided by the left pier?
29,500 N
Which will roll down an incline in the shortest time, a can filled with water or the same can filled with ice?
a) water
b) ice
c) both the same
d) not enough information is given
a) water
A 0.40 kg ball on a 5.0 m string rotates in a circular path in a vertical plane.
If the angular speed of the ball at the bottom of the circle is 8.0 rad/s, what is the force that maintains circular motion?
13 N