Question

Calaculate the kinetic energy of
a 20 Kg wooden Cart mobing with a speed of 5 m/s Calculate the kinetic energy again when the speed is doubled ​

Answer 1

Answer: 250 J and 1000 J.

Given:

$\sf Mass (m)=20 \:kg$

$\sf Velocity( v)=5 \:m/s$

To find:

$\bullet\:\textsf{The kinetic energy (K.E)}$

$\bullet\:\textsf{The kinetic energy (K.E) when the speed is doubled.}$

Formula used:

$\boxed{\sf Kinetic\: Energy\:(K.E)=\dfrac{1}{2}Mass(m)\times Velocity(v)^2}$

Explanation:

$\textsf{According to the question,}$

$\sf m=20\: kg\:and\:v=5\:m/s$

$\textsf{Substituting the values in the formula, we get:}$

$\Rightarrow \sf K.E=\dfrac{1}{2}\times 20\times 5^2$

$\Rightarrow \sf K.E=\dfrac{1}{2}\times 20\times 25$

$\Rightarrow \sf K.E=10\times 25$

$\Rightarrow \boxed{\sf K.E=250\: J}$

$\textsf{Let v' be the new velocity when the speed is doubled} \therefore$

$\Rightarrow\sf v'=v\times 2$

$\Rightarrow\sf v'=5\times 2$

$\Rightarrow\sf v'=10\:m/s$

$\textsf{Substituting the values in the formula, we get:}$

$\Rightarrow \sf K.E=\dfrac{1}{2}\times 20\times 10^2$

$\Rightarrow \sf K.E=\dfrac{1}{2}\times 20\times 100$

$\Rightarrow \sf K.E= 10\times 100$

$\Rightarrow \boxed{\sf K.E=1000\: J}$

Hence, the kinetic energy is 250 J and when its speed is doubled, then kinetic energy will be 1000 J.