A uniform narrow bar, resting on frictionless ice, is given a transverse horizontal impulse at one end as shown.The center of mass of the bar COM will then:
A)remain at rest
B)move in a circle
C)move in a straight line
D)move in a parabola
E)move along some other curve

Question

A uniform narrow bar, resting on frictionless ice, is given a transverse horizontal impulse  at one end as shown.The center of mass of the bar COM will then: 
A)remain at rest 
B)move in a circle 
C)move in a straight line 
D)move in a parabola 
E)move along some other curve

Quizplus · Accepted Answer

Since the bar is resting on frictionless ice, there is no external force acting on it after the impulse is given. As the impulse is given at one end of the bar, the bar will start to rotate about its center of mass. However, since there is no external force acting on the center of mass, it will continue to move in a straight line with a constant velocity. Therefore, the correct choice is C) move in a straight line.

A Uniform Narrow Bar, Resting on Frictionless Ice, Is Given