Question:
A particle $(m=1 \mathrm{~kg})$ slides down a frictionless track
(AOC) starting from rest at a point $A$ (height $2 \mathrm{~m}$ ).
After reaching $C$, the particle continues to move freely
in air as a projectile. When it reaching its highest
point $P$ (height $1 \mathrm{~m}$ ), the kinetic energy of the particle
(in $J$ ) is: $($ Figure drawn is schematic and not to scale;
take $g=10 \mathrm{~ms}^{-2}$ )
Solution:
$(10.00)$
Kinetic energy $=$ change in potential energy of the
particle,
$\mathrm{KE}=\mathrm{mg} \Delta \mathrm{h}$
Given, $m=1 \mathrm{~kg}$
$\Delta h=\mathrm{h}_{2}-\mathrm{h}_{1}=2-1=1 m$
$\therefore K E=1 \times 10 \times 1=10 J$