Question

An object takes 5 S to reach the ground from a height of 5m on a planet.What is the value of g on the planet ? (answer in steps)​

Answer 1

Time taken = 5 seconds

Height = 5 m

Now,

Distance travelled by the ball will be same as the height at which the ball is kept.

Thus,

Distance covered = 5 m

Now,

Initial velocity will be 0 m/sec

This is because, the object is undergoing free fall.

From the 3rd equation of motion we have :-

$s = ut + \frac{1}{2}a {t}^{2}$

Now,

Putting down the values :-

$5 = 0 \times 5 + \frac{1}{2}a {5}^{2} \\ \\ \\5 = \frac{25}{2}a \\ \\ \\a = \frac{2 \times 5}{25} \\ \\ \\a = \frac{2}{5} \\ \\ \\a = 0.4$

Thus,

g on that planet is equal to 0.4 m/sec²