Question

A body is thrown vertically upwards and rises to a height of 10 m. The velocity with which the body was thrown upwards is $(g=9.8m/s^2).$

• A. 10 m/s
• B. 20 m/s
• C. 14 m/s
• D. None of these

Answer 1

The correct option is C

14 m/s

Step 1: Given data:

1. A body is thrown vertically upwards.
2. The body rises to a height of 10 m.

We know that;

1. Upon reaching the height, the final velocity $v$ becomes zero.
2. Acceleration due to gravity is 9.8 m/s², which will be negative as the body goes against gravity.

Step 2: Finding the speed:

Considering 3^rd equation of motion,

$v^2-u^2=2gh$

$$\begin{gathered} {\left(0\right)}^2-u^2=2\left(-9.8\right)10 \\ -u^2=-196 \\ u=\sqrt{196} \\ u=+14m/s. \end{gathered}$$

Therefore, the velocity with which the body is thrown upwards is 14 m/s.

Hence, the correct option is (C).