Two people sit on a seesaw. They sit in positions such that the
seesaw is balanced in a horizontal position. True/False: The two people must weigh the
same amount.
☐ true
☑ false
In order to apply the
most torque to a screw, you should:
☑ use a wrench with a long handle
☐ use a wrench with a short handle
☐ there would be no difference
A meterstick is hung
from a string attached to its middle, the "50 cm" mark. A rock (1 kg) is tied to
the stick at the "0 cm" mark. A second rock, (2 kg) is also tied to the
stick. If the system is balanced, where must the second rock be?
☐ at the 25 cm mark
☐ at the 50 cm mark
☑ at the 75 cm mark
☐ at the 100 cm mark
☐ none of the above
Ralph noticed that both torque and work are
obtained by multiplying a force times a distance. He wants to know: how are they different?
Do
they have the same units? What can you tell Ralph to help him out?
One difference is that work is done on an object over a period of time, whereas torque is basically a force applied to the object at an instant of time. They do have the same units, but represent very different things. Therefore the units of torque are usually written as Nm, whereas the units of energy & work are usually written as J.