Question Details

If mass speed and radius of rotation of a body moving in a circular path are all increased by 50%, the necessary force required to maintain the body moving in the circular path will have to be increased by

Options

A

225%

B

125%

C

150%

D

100%

Correct Answer :

125%

Solution :

The centripetal force required to keep a body of mass m moving in a circular path of radius r with a speed v is given by the formula:

F=mv2r

According to the question, the mass, speed, and radius of rotation are all increased by 50%. This means the new values (denoted by prime symbols) can be expressed as:

New mass, m=m+0.5m=1.5m
New speed, v=v+0.5v=1.5v
New radius, r=r+0.5r=1.5r

Let us calculate the new force, F, using these new values:

F=m(v)2r

Substitute the expressions for the new values into the formula:

F=(1.5m)(1.5v)21.5r

Simplify the expression by expanding the squared term in the numerator:

F=1.5m2.25v21.5r

Cancel the common factor of 1.5 in both the numerator and the denominator:

F=2.25mv2r

Since the original force is F=mv2r, we can write:

F=2.25F

The fractional increase in the necessary force is calculated as:

F-FF=2.25F-FF=1.25

To find the percentage increase, multiply this fractional increase by 100:

Percentage Increase=1.25×100=125%

Thus, the force must be increased by 125% to maintain the body moving in the circular path.

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