Concepts Of Physics MCQ Edition [Volume 1]
- Exam
- Concepts Of Physics MCQ Edition [Volume 1]
- Subject
- Physics
- Chapter
- Centre of Mass, Linear momentum, Collision
Concepts Of Physics MCQ Edition [Volume 1] · Physics · Centre of Mass, Linear momentum, Collision
A ball placed inside a closed box travels around, making collisions...
A ball placed inside a closed box travels around, making collisions with the walls. The box is situated on a smooth surface. The velocity of the centre of mass
Options
- Aof the ball relative to the box remains constant
- Bof the box plus the ball system remains constant
- Cof the box remains constant
- Dof the ball remains constant
Correct answer
B. of the box plus the ball system remains constant
Step-by-step solution
Since the box is placed on a smooth surface, there is no external force acting on the system comprising the box and the ball in the horizontal direction.
According to the law of conservation of linear momentum, if the net external force on a system is zero, the velocity of its centre of mass remains constant.
The collisions between the ball and the walls of the box are internal forces, which do not affect the motion of the centre of mass of the system.
Therefore, the velocity of the centre of mass of the box plus the ball system remains constant.
According to the law of conservation of linear momentum, if the net external force on a system is zero, the velocity of its centre of mass remains constant.
The collisions between the ball and the walls of the box are internal forces, which do not affect the motion of the centre of mass of the system.
Therefore, the velocity of the centre of mass of the box plus the ball system remains constant.