Circle the right answers.

I. Three equal masses are arranged in a configuration as shown in the figure. Which point best represents the position of the center of mass?

    A.    Point A
    B.    Point B
    C.    Point C
    D.    Point D
    E.    Point E
Ans. D
 
 

II. The potential energy stored in a spring is 6J when it is compressed by 1cm from its natural length. What is the potential energy stored when it is compressed by 2cm?

    A.    0J
    B.    -6J
    C.    3J
    D.    12J
    E.    24J

Ans. E

III. A 1 kg lump of clay traveling at 2m/s smashes into another 1 kg lump of clay which is not moving. Smush! They stick and become one 2 kg lump. What is the speed of the 2 kg lump?

    A.    0 m/s
    B.    1 m/s
    C.    1.41 m/s
    D.    2 m/s
    E.    4 m/s

Ans. B

IV. Two satellites A and B of the same mass are going around Earth in concentric orbits. The distance of satellite B from Earth's center is three times that of satellite A. What is the ration of the tangential speed of B to that of A?

    A.    
    B.    3
    C.    
    D.    
    E.    None of above

Ans. D