Question:
A ball is thrown upwards, it takes $4 s$ to reach back to the ground. Find its initial velocity :
A ball is thrown upwards, it takes $4 s$ to reach back to the ground. Find its initial velocity :
Updated On: Jul 27, 2022
- $ 30\,ms^{-1} $
- $ 10\,ms^{-1} $
- $ 40\,ms^{-1} $
- $ 20\,ms^{-1} $
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Verified By Collegedunia
The Correct Option is D
Solution and Explanation
Since, the ball is thrown upwards and it reaches back, so time to reach maximum height is half of total time i.e., $t_{\max }=2 s$.
Also speed at maximum height is zero, so
$0=u-g t_{\max } $
$\Rightarrow u=g t_{\max }=20 \,ms ^{-1} \,\,\left(\because g =10 ms ^{-2}\right)$
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Concepts Used:
Motion in a straight line
The motion in a straight line is an object changes its position with respect to its surroundings with time, then it is called in motion. It is a change in the position of an object over time. It is nothing but linear motion.
Types of Linear Motion:
Linear motion is also known as the Rectilinear Motion which are of two types:
- Uniform linear motion with constant velocity or zero acceleration: If a body travels in a straight line by covering an equal amount of distance in an equal interval of time then it is said to have uniform motion.
- Non-Uniform linear motion with variable velocity or non-zero acceleration: Not like the uniform acceleration, the body is said to have a non-uniform motion when the velocity of a body changes by unequal amounts in equal intervals of time. The rate of change of its velocity changes at different points of time during its movement.