Question

A ball of density $\rho$ is dropped from a height on the surface of a non-viscous liquid of density $2\rho$ Choose the correct options.

• A. Motion of ball is periodic but not simple harmonie
• B. Acceleration of ball in air and in liquid are equal
• C. Magnitude of upthrust in the liquid is two times the weight of ball
• D. Net force on ball in air and in liquid are equal and opposite

Answer 1

The correct option is A Motion of ball is periodic but not simple harmonie

In air $a_1=g$ (downwards)
In liquid $a_1=\frac{upthrust-weight}{mass}$

$=\frac{\left(V\right)\left(2\rho \right)\left(g\right)-\left(V\right)\left(\rho \right)\left(g\right)}{\left(V\rho g\right)}$
$=g$ (upwards)
$\therefore$ $a_1\ne a_2$