A car falls off a ledge and drops to the ground in $0.5$ second. Let $g=10 \mathrm{m} {\mathrm{s}}^{-2}$, then what is its speed on striking the ground?

To find the density of a liquid, a student used the following steps. The sequence of steps followed is given. Identify the step which has an error.

1: Found the weight ($W$) of the body in air.

2: Collect displaced volume of water to know the volume $V$ of immersed body.

3: Found the weight $W_l$ of the body in water when immersed completely.

4: Found $\frac{W}{V}$ to get the result.