Question

The weight of a person on a planet A is about half that on the earth. He can jump upto $0.4m$ height on the surface of the earth. How high he can jump on the planet A ?

• A. $0.8m$
• B. $1m$
• C. $1.2m$
• D. $1.4m$

Answer 1

The correct option is A $0.8m$

mass $mkg$

let, weight of the man on earth $W_1$

weight of the man on planet A $W_2$

given: $W_2=\frac{W_1}{2}$

or $m{g}^{{}^{\prime }}=\frac{mg}{2}$

or $g^{{}^{\prime }}=\frac{g}{2}$

potential energy used by him to jump height of $0.4m$ on earth is $0.4mg$.

if he apply same potential energy on planet A with acceleration due to gravity $g^{{}^{\prime }}$ he would move a height $h^{{}^{\prime }}$

so,$mgh=m{g}^{{}^{\prime }}{h}^{{}^{\prime }}$

since,$\frac{g}{2}=g^{{}^{\prime }}$

$g\times 0.4=\frac{g}{2}{h}^{{}^{\prime }}$

so, $h^{{}^{\prime }}=0.8m$

hence, he can jump on the planet A up to height of $0.8m$.