A uniform narrow bar, resting on 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 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

According to Newton's first law of motion, an object in motion (or at rest) will continue to be in motion (or at rest) in a straight line with a constant speed unless acted upon by an external force. Since the impulse given to the bar is horizontal and transverse, it will cause the bar to move in a straight line in the direction of the impulse. The center of mass of the bar will also move in a straight line with a constant speed, assuming no other external forces act upon it. Therefore, the correct answer is (C) move in a straight line.

A Uniform Narrow Bar, Resting on Ice, Is Given a Transverse