Question

14. How fast should a man of 50 kg run so that his kinetic energy be 625J?
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Answer 1

Answer:

We have to find the speed of the running man. We have,

Mass of the man (m) = 50 kg

Kinetic energy of the man (K.E) = 325 J !! So, we use the expression of kinetic energy to find the unknown quantity as,

K.E = 1/2 mv^2

Where,

KE - Kinetic Energy

m - Mass

v - Speed

So,

'v = sqrt((2(K.E))/((m))`

Therefore, `v = sqrt(2(625))/((50))` m/s

= 'sqrt(25)' m/s =

5 m/s

So , the man should be running with a speed of 5 m/s