Question

A particle of mass $2mg$ moves with constant speed and is found to pass two points $5.0m$ apart in a time interval of $5ms$ . Find the kinetic energy of the particle

• A. 1.0 J
• B. 2.0 J
• C. $3.0J$
• D. $4.0J$

Answer 1

Answer: (A)

Given, mass $=2mg=2\times 10^{-6}kg$
Distance $=5.0m$
Time $t=5ms=5\times 10^{-3}s$
To find $KE$ = ?
Now, velocity $\frac{\text{Distance}}{\text{Time}}=\frac{5}{5\times 10^{-3}}m/s$
$=1000m/s$
and $KE=\frac{1}{2}m{v}^2=\frac{1}{2}\times 2\times 10^{-6}{\left(10^3\right)}^2$
$=1J$