The Physical World I

Spring 2005
MWF 11:30

Instructor: Dr. Bruce Law, CW 327, Tel: 532-1618.
 

REVIEW QUESTIONS OF Home Work 8

R26. The force on the can is provided by the string and is directed along the string towards the center of the circle.

R27. An inward force acts of the clothes and causes them to go in a circle. In the absence of this force the clothes would travel in a straight line at constant speed according to Newton`s first law.

R28. No force. The string provides a force that acts on the can and causes the can to move in a circular path. In the absence of this force, according to Newton`s first law, the can continues to move in a straight line path once the string has broken.

R29. No force. Your seat belt would have provided a force on you if you were wearing it, however, as you are not wearing the seat belt you continue in a straight line path as the car rounds a corner and consequently slam into the car door.

 

EXCERISES OF Home Work 8

E38. As the space habitat is rotating, her velocity direction is changing with time. Therefore, she is accelerating and hence a net force is acting on her according to Newton 2, F(net) = ma. This net force, or centripetal force, is pointing towards the axis of rotation. If there was no net force, she would continue to move in a straight line (Newton 1). The centripetal force, which is caused by the outer walls of the habitat, makes her move in a circle and it feels as though she is being pulled by artificial gravity towards the outer wall.