Part A: Suppose you raise a box that has mass \"m\" off the floor to the height
ID: 1567119 • Letter: P
Question
Part A:
Suppose you raise a box that has mass "m" off the floor to the height "y" of a table that is "x" meters away from you. You then slowly walk to the table and set the box gently on it. In physics terms, how much work do you do in this task?
a. W=mgx
b. W = mgy
c. W = - mgy
d. W=mg(x+y)
Part B:
How does the tension T in a wire or string affect the speed of the wave when the string vibrates?
d. The speed of the wave does not depend on the tension in the wire
a. The speed increases with the
b. The speed of the wave is proportional to the tension
c. The speed decreases as T increases and goes as
d. The speed of the wave does not depend on the tension in the wire
Explanation / Answer
Part A
Work done depends upon the change in final and initial position of the box.
As stated in the question, box is lifted upto height y, and man moves distance x along horizontal. But the work will be counted on y only, because by moving x, there is no change in height, so no work is done is done against gravity. But in case of y, there is change in height. So, work will be done against gravity and it will be equal to mgy.
Answer b.
Part B.
Speed of wave is given by (T/Mass density) power 1/2
Thus we can see, speed of wave is proprotional to square root of tension in the string.
Answer a.