Question

A block is thrown upwards with a kinetic energy of $1\text{J}$. It goes up to a maximum height of $1\text{m}$. Find the mass of the block.
$[g=10{\text{m/s}}^2]$

• A. $10\text{g}$
• B. $100\text{g}$
• C. $10\text{kg}$
• D. $100\text{kg}$

Answer 1

The correct option is B $100\text{g}$

From Law of Conservation of Mechanical Energy,

$P{E}_i+K{E}_i=P{E}_f+K{E}_f$

$\Rightarrow 0+1=mgh+0$

$\Rightarrow m=\frac{1}{gh}=\frac{1}{10\times 1}=0.1\text{kg}=100\text{g}$