Question

A ball is thrown vertically upwards. It is at the same height $h$ after $10$ and $20$ seconds. Then the value of $h$ is (assume $g=9.8m/s^2$)

• A. $270$ meters
• B. $360$ meters
• C. $490$ meters
• D. $980$ meters

Answer 1

The correct option is D $980$ meters

We know that,
$s=ut+\frac{1}{2}a{t}^2$
So,
$h=u\times 10-\frac{1}{2}\times 9.8\times (10{)}^2\cdots (1)h=u\times 20-\frac{1}{2}\times 9.8\times (20{)}^2\cdots \left(2\right)$
Using equation (1) and (2),
$h=9.8\times 100=980$ meters