Physics Rotational Mechanics Level: High School
Uniform circular motion
An object is moving in a circular path with an angular speed of 1.52 rad/s . How long does it take the object to complete one revolution ?
a) 4.13 s
b) 2.07 s
c) 118 s
d) 4.77 s
Physics Rotational Mechanics Level: High School
Centre of mass
A 60.0 kg man stands at one end of a 20.0 kg uniform 10.0 m long board . How far from the man is the center of mass of the man-board system ?
a) 1.25 m
b) 2.50 m
c) 5.00 m
d) 7.50 m
Physics Rotational Mechanics Level: High School
Suppose the motor has a bearing shaft diameter of 3.2 cm and the coefficient of friction of each bearing is 0.008 . Find the torque of friction of the bearings .1) 0.0320 N-m
2) 0.314 N-m
3) 0.411 N-m
4) 0.481 N-m
Physics Rotational Mechanics Level: High School
If the power to the motor is shut off while the motor is running at 3000 rpm and a brake is applied , how much heat is joules will be dissipated in the brake in order to bring the motor to a stop ?1) 441 J
2) 4410 J
3) 12340 J
4) 138527 J
Physics Rotational Mechanics Level: High School
What horsepower is developed by the motor while running at 3000 rpm and delivering a torque of 120 N-m to a load ?1) 24.2 hp
2) 37.7 hp
3) 50.5 hp
4) 88.8 hp
Physics Rotational Mechanics Level: High School
Assume the torque stays constant at 120 N-m. How long will it take for the unloaded armature to accelerate from zero up to full speed of 3000 rpm ?1) 7.02 sec
2) 7.35 sec
3) 34.1 sec
4) 70.2 sec
Physics Rotational Mechanics Level: High School
The torque required to turn the crank on an ice cream maker is 4.50 Nm . How much work does it take to turn the crank through 300 full turns ?a) 4240 J
b) 8480 J
c) 1350 J
d) 2700 J
Physics Rotational Mechanics Level: High School
A solid wood door , 90.0 cm wide by 2.00 m tall has a mass of 35.0 kg .It is ajar and at rest . A ball with a mass of 500 g is shown thrown perpendicular to the door with a speed of 20.0 m/s and hits the door 60.0 cm from the hinged side . The ball rebounds with a speed of 16.0 m/s along the same line . What is the angular speed of the door after the collision ?a) 0.127 rad/s
b) 0.925 rad/s
c) 1.14 rad/s
d) 4.57 rad/s
Physics Rotational Mechanics Level: High School
A figure skater is spinning slowly with arms outstretched . She brings her arms in close to her body and he moment of inertia decreases by ½ . He angular speed increases by a fact of .a) 2
b) 4
c) The square root of (2)
d) ½
Physics Rotational Mechanics Level: High School
A uniform meter stick with a mass of 135 g rotates about an axis perpendicular to the stick passing through the center of stick with an angular speed of 3.50 rad/s squared . What is he magnitude of the angular momentum of the stick ?a) 0.0394 k x m squared / s .
b) 0.473 k x squared / s .
c) 0.158 k x squared / s .
d) 0.0236 k x squared / s .
Physics Rotational Mechanics Level: High School
A meter stick balances at the 50.0 cm mark . If a mass of 50.0 g is placed at the 90.0 cm mark , the stick balances at the 61.3 cm mark . What is the mass of the meter stick ?a) 127 g
b) 178 g
c) 32.6 g
d) 73.4 g
Physics Rotational Mechanics Level: High School
An 82.0 kg diver stands at the edge of a light 5.00 m diving board , which is supported by two pillars 1.60 m apart . Find the force exerted by pillar B .a) 1.71 kN downwards
b) 1.71 kN upwards
c) 2.51 kN downwards
d) 2.51 kN upwards.
Question Diagram
Physics Rotational Mechanics Level: High School
A 320-g mass and a 400-g mass are attached to the two ends of a string that goes over a pulley with a radius of 8.70 cm. Because of friction , the pulley does not begin to rotate , What is the magnitude of the frictional torque on the bearing of the pulley if the system is in static equilibrium ?a) 0.00683 Nm
b) 0.614 Nm
c) 0.626 Nm
d) 0.000696 Nm
Physics Rotational Mechanics Level: High School
A man is holding an 8.00- kg vacuum cleaner at arm’s length , a distance of 0.55 m from his shoulder , What is the torque on the shoulder joint if the arm is horizontal ?a) 4.40 Nm
b) 43.2 Nm
c) 14.5 Nm
d) 0 Nm
Physics Rotational Mechanics Level: High School
A 10.5 kg board is wedged into a corner and held by a spring at a 50.0 angle , as the drawing shows . The spring has a spring constant of 182 N/m and is parallel to the floor . Find the amount by which the spring is stretched from its unstrained length .
Question Diagram
