Question

A ball is thrown vertically upward with a speed of 30 m/s. The magnitude of its displacement after 3s will be ________.

(Take g = 10 m/s²)
1. 50 m
2. 45 m
3. 65 m
4. 80 m

Answer 1

Correct Answer - Option 2 : 45 m

The correct answer is 45 meters.

Given,

Initial Velocity (u) = 30 m/s.

Acceleration due to gravity (g) = -10 m/s² (-ve because of Upward motion).

Time (t)= 3 Seconds.

Displacement (s) = ?

Using the equation:

\(s= ut +{1 \over 2} at^2\)

\(s= (30\times3)+{1\over2}\times(-10)\times3^2=90-45=45 \ m\)

∴ The magnitude of its displacement after 3 s will be 45 meters.