Question

Brandon Stark saw some suspicious activity at the terrace of a tower. When he reached there, he saw some thieves and hurried back to tell his father. Accidentally, he fell from the top of the tower and landed on the ground exactly 2 seconds later. Find the height of the tower. Take $g=10m{s}^{-2}$

• A. 5 m
• B. 10 m
• C. 15 m
• D. 20 m

Answer 1

The correct option is D 20 m

Brandon experienced a free fall from the top of the tower and, thus, was under the acceleration due to gravity (g).

Distance travelled in 2 seconds is equal to the height of tower which can be found out by applying equation of motion.

From second equation of motion, we have,
$s=u\times t+\frac{1}{2}\times g{t}^2$
where s- height of tower, u- initial velocity, t-time taken and g- acceleration due to gravity.
Since he fell from rest, u = 0
$s=\frac{1}{2}\times g{t}^2=\frac{1}{2}\times 10\times 2^2=20m$
Therefore, height of tower is 20 m.