Question

If a man speeds up by 1 m/s, his kinetic energy
increases by 44%. His original speed in m/s is
(1) 1
(2) 2
(3) 5
(4) 4​

Answer 1

Answer:

option 3 is the carect answer

Answer 2

Answer:

The original velocity is 5 metre per second.

Explanation:

As we all know that kinetic energy is given by the formula mass into velocity squared by 2.

Let us assume here that the kinetic energy initially is $\frac{1}{2} mv^2.$

In the given question the speed of the person is increasing by 1 metre per second so now the new kinetic energy becomes $\frac{1}{2} m(v+1)^2.$

The new kinetic energy as given has increased by 44%.

So we can say it becomes 1.44 times original kinetic energy on putting the values and solving the equation we get

                             $\frac{1}{1.44} = \frac{v^2}{(v+1)^2}$

                           $= \frac{(v+1)}{v}$ = 1.2

                                       v= 5m/s.