How Fast Should a Man of 50 Kg Run So that His Kinetic Energy Be 625 J? - Science

Short Note
Sum

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

Solution

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 .

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APPEARS IN

Lakhmir Singh Science Class 9 Physics
Chapter 4 Work and energy
Very Short Answers | Q 14 | Page 145