
Two balls A and B of same masses are thrown from the top of the building. A, thrown upward with velocity \[u\] and B, thrown downward with velocity $u$, then
A. Velocity of A is more than B at the ground
B. Velocity of B is more than A at the ground
C. Both A & B strike the ground with same velocity
D. None of these
Answer
163.8k+ views
Hint:In this question, we are given that there are two balls of same mass and same velocity are thrown from the top of the building but first one thrown in the upward direction and the other one in the other direction. We Have to find the relation between their velocities. Apply the third equation of motion and put the given values to calculate the velocity.
Formula used:
Third equation of the motion –
${v^2} = {u^2} + 2gh$
Here, $v = $ final velocity of the body
$u = $ initial velocity
$g = $ acceleration due to the gravity
$h = $ height
Complete answer:
Let, the height of the building be $h$ and the masses of the balls be $m$
Given that,
Initial speed of the ball A $ = v$
Initial velocity of the ball B $ = - v$
Here, ball are moving in upward and backward direction. So, for the backward direction assume the initial velocity to be negative.
Both balls are moving under the same acceleration. Assume it to be acceleration due to the gravity.
Let, the final velocity of ball A and B be ${v_A}$ and ${v_B}$ respectively.
Using the third equation of the motion i.e., ${v^2} = {u^2} + 2gh$
Substituting the required values,
For Ball A,
${v_A}^2 = {v^2} + 2gh$
On solving, we get ${v_A} = \sqrt {{v^2} + 2gh} $
For Ball B,
${v_B}^2 = {\left( { - v} \right)^2} + 2gh$
On solving, we get ${v_A} = \sqrt {{v^2} + 2gh} $
Thus, ${v_A} = {v_B}$
Hence, option (C) is the correct answer i.e., Both A & B strike the ground with same velocity.
Note:The phrases velocity and speed describe how fast or slow an object moves. We frequently encounter circumstances in which we must determine which of two or more things is travelling faster. If they are travelling in the same direction on the same road, it is easy to identify who is going faster. However, determining who is the fastest is difficult if their motions are in opposite directions. In such instances, the concept of velocity comes in handy.
Formula used:
Third equation of the motion –
${v^2} = {u^2} + 2gh$
Here, $v = $ final velocity of the body
$u = $ initial velocity
$g = $ acceleration due to the gravity
$h = $ height
Complete answer:
Let, the height of the building be $h$ and the masses of the balls be $m$
Given that,
Initial speed of the ball A $ = v$
Initial velocity of the ball B $ = - v$
Here, ball are moving in upward and backward direction. So, for the backward direction assume the initial velocity to be negative.
Both balls are moving under the same acceleration. Assume it to be acceleration due to the gravity.
Let, the final velocity of ball A and B be ${v_A}$ and ${v_B}$ respectively.
Using the third equation of the motion i.e., ${v^2} = {u^2} + 2gh$
Substituting the required values,
For Ball A,
${v_A}^2 = {v^2} + 2gh$
On solving, we get ${v_A} = \sqrt {{v^2} + 2gh} $
For Ball B,
${v_B}^2 = {\left( { - v} \right)^2} + 2gh$
On solving, we get ${v_A} = \sqrt {{v^2} + 2gh} $
Thus, ${v_A} = {v_B}$
Hence, option (C) is the correct answer i.e., Both A & B strike the ground with same velocity.
Note:The phrases velocity and speed describe how fast or slow an object moves. We frequently encounter circumstances in which we must determine which of two or more things is travelling faster. If they are travelling in the same direction on the same road, it is easy to identify who is going faster. However, determining who is the fastest is difficult if their motions are in opposite directions. In such instances, the concept of velocity comes in handy.
Recently Updated Pages
Uniform Acceleration - Definition, Equation, Examples, and FAQs

JEE Main 2021 July 25 Shift 1 Question Paper with Answer Key

JEE Main 2021 July 22 Shift 2 Question Paper with Answer Key

JEE Atomic Structure and Chemical Bonding important Concepts and Tips

JEE Amino Acids and Peptides Important Concepts and Tips for Exam Preparation

JEE Electricity and Magnetism Important Concepts and Tips for Exam Preparation

Trending doubts
JEE Main 2025 Session 2: Application Form (Out), Exam Dates (Released), Eligibility, & More

Atomic Structure - Electrons, Protons, Neutrons and Atomic Models

Displacement-Time Graph and Velocity-Time Graph for JEE

JEE Main 2025: Derivation of Equation of Trajectory in Physics

Learn About Angle Of Deviation In Prism: JEE Main Physics 2025

Electric Field Due to Uniformly Charged Ring for JEE Main 2025 - Formula and Derivation

Other Pages
JEE Advanced Marks vs Ranks 2025: Understanding Category-wise Qualifying Marks and Previous Year Cut-offs

NCERT Solutions for Class 11 Physics Chapter 1 Units and Measurements

Units and Measurements Class 11 Notes: CBSE Physics Chapter 1

NCERT Solutions for Class 11 Physics Chapter 2 Motion In A Straight Line

Motion in a Straight Line Class 11 Notes: CBSE Physics Chapter 2

Important Questions for CBSE Class 11 Physics Chapter 1 - Units and Measurement
