A ball A is dropped from a building of height $ 45\, m $ . Simultaneously another identical ball $ B $ is thrown up with a speed $ 50 \,m \,s^{-1} $ . The relative speed of ball $ B $ w.r.t. ball A at any instant of time is (Take $ g = 10\, m \,s^{-2}) $
Updated On: Jul 5, 2022
$ 0 $
$ 10\,m\,s^{-1} $
$ 25\,m\,s^{-1} $
$ 50\,m\,s^{-1} $
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The Correct Option isD
Solution and Explanation
Here, $ u_A = -0 $ , $ u_B = +50\, m\, s^{-1} $$ a_{A}=-g $ , $ a_{B}=-g $$ u_{BA}=u_{B}-u_{A}=50\,m\,s^{-1}-(-0)\,m\,s^{-1}=50\,m\,s^{-1} $$ a_{BA}=a_{B}-a_{A}=-g-\left(-g\right)=0 $$ \because v_{BA}=u_{BA}+a_{BA}t\quad\left(As\,a_{BA}=0\right) $$ \therefore v_{BA}=u_{BA} $
As there is no acceleration of ball $ B $ w.r.t to ball $ A $ , therefore the relative speed of ball $ B $ w.r.t ball $ A $ at any instant of time remains constant $ ( = 50\, m\, s^{-1}) $ .
The motion in a straight lineis 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.
