A ball of mass 2 kg traveling at 8 ms-1 strikes a ball of mass 4 kg traveling at 2 ms-1. Both balls are moving along the same straight line as shown. After the collision, both balls move at the same velocity v. What is the magnitude of the velocity v?
Correct answer: A. 4 ms-1
- A. 4 ms-1
- B. 5 ms-1
- C. 6 ms-1
- D. 8 ms-1
- E. 10 ms-1
Explanation
Option A is correct when we apply the law of conservation of momentum as mv= m1v1+ m2v2 m=m1+m2 = 2+4 = 6kg. m1 = 2kg, m2= 4kg , v1= 8ms-1, v2=2ms-1 Thus , 6xV= 2x8 + 4x2 V= (16+8)/6=4ms-1 Hence, all other options are incorrect.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Force and Motion
Displacement, velocity and acceleration describe motion, including the horizontal and vertical components of projectile motion. The chapter connects these quantities with Newton's laws, momentum and impulse, then applies conservation of momentum to collisions, distinguishing elastic collisions from inelastic ones.
Practise Force and Motion
1,416 free Force and Motion MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Force and Motion questions
A box of mass m = 6 kg slides with speed v = 4 m/s across a frictionless floor. It explodes into two pieces: one piece, with mass m1 = 2 kg move in the same direction with speed v1 = 8 m/s. Find the velocity of the second piece.
Two blocks, X and Y, of masses m and 2m respectively are accelerated along a smooth horizontal surface by a force F applied to block X, as shown in the diagram. What is the magnitude of the force exerted by block Y on block X during this acceleration?
A ball is thrown vertically upward with the velocity of 98 m/sec, how high does the ball rise?
A rock is thrown straight upward from the edge of a 30 m cliff, rising 10 m then falling all the way down to the base of the cliff. Find the rock's displacement.
A moon of mass 'm' orbits a planet of mass 100 m. Let the strength of the gravitational force exerted by the planet on the moon be denoted by F1, and let the strength of the gravitational force exerted by the moon on the planet be F2. Which of the following is true?
If a car collides with a housefly, what will be the magnitude of the force experienced by the housefly?