Chapter 6
1. A motor rotates at 3600 RPM. Convert this number into rad/s.
2. A go-kart is made by mounting a washing machine motor onto a cart. The
motor drives a wheel of radius 6in. If the motor is spinning at 2.0rad/s. how
fast is the cart moving in in/s?
3. A wheel of diameter 10cm is spinning at 200RPM and is driving another
wheel of diameter 5cm. How fast is the driven wheel spinning(in RPM)?
4. The head bolts on a certain car require they be tightened with a torque of
110ftLb. You are able to push on the wrench with 50Lb of force. How long
should the wrench be?
5. The specification plate on a motor states the motor operates at 110V,
draws 4A and runs at 3600RPM. What is the torque of this motor?
(Remember to convert RPM into rad/s !).
6. The transmission on a car is designed to change the RPM and torque of an
engine to the proper levels at the wheels to drive the car effectively. If the
engine has 130ftLb of torque and the torque at the wheels is 260 ftLb, how
many times bigger is the driven wheel compared to the driving wheel?
7. What is the centripetal force on a 75kg man turning a corner of radius
100m in a car at and angular velocity of 1.1rad/s?
8. A 2000Lb car exits off the express way onto an exit ramp at 45mph or
66ft/s. The ramp had a turning radius of 300ft. What is the centripetal force
on the car? (remember to convert weight to mass!)
9. A robot moves across the floor on wheels of radius 2in wheels rotating at
25RPM. How fast is the robot moving in in/s?
10. An conveyer belt requires 22Lb of force to move. Mounted on the shaft
of the motor that drives the belt is a wheel of radius 6in. What torque must
the motor have in ftLb?
11. A motor is spinning at 1750 RPM. What is this in rad/s?
12. What is the angular velocity of the earth on its own axis in rpm?
13. The carriage on a copy machine is translated back and forth on wheels of
radius 1.0cm. If the wheels are spinning at 5rpm,how fast is the carriage
moving in cm/min?
14. A motor rotating at 50rpm is connected to a wheel of radius 12cm. This
wheel is driving another wheel of radius 4cm.How fast is the 4cm wheel
spinning?
15. A cart on wheels requires 8N of force to keep it moving steadily. If the
cart is driven by a motor connected to a wheel of radius 0.03m, what torque
is the motor generating?
16. If the motor in the previous problem is spinning at 25rpm, how much
power is the motor generating?
17. A motor has a torque of 1.1Nm with a gear on its shaft with 20 teeth.
Another gear is being driven by this gear with 60 teeth. What is the torque of
the driven gear?
18. A mass of 0.4kg is placed on a turntable at a distance of 0.10m from the
center of rotation. If the turntable is spinning at 45rpm, what is the
centripetal force on the mass?
19. The wheels on a cart of radius 2.0in turn through 50 revolutions. How far
has the cart moved?
20. A wheel of diameter 10cm spinning at 200rpm drives another wheel of
diameter 5cm. How fast is the driven wheel spinning?