a boy is running with a kinetic energy of 810 j if the boy has a mass of 80 kg whats his speed?
If the boy started at rest then its speed would be equal to 4.5 m/s squared.
Answer:
The speed of boy is 4.5 m/s
Explanation:
Given that,
Kinetic energy = 810 J
Mass = 80 kg
We need to calculate the speed
Using formula of kinetic energy
\(K.E=\dfrac{1}{2}mv^2\)
Where, m = mass
v = speed
Put the value into the formula
\(810=\dfrac{1}{2}\times80\times v^2\)
\(v^2=\dfrac{2\times810}{80}\)
\(v=\sqrt{\dfrac{2\times810}{80}}\)
\(v=4.5\ m/s\)
Hence, The speed of boy is 4.5 m/s.