PHYSICS CLASS 7

1. A perfectly elastic collision is defined as one in which there is no loss of__________in the collision

• Potential energy

• Kinetic energy

• Both1&2

• None of the above

2.After collision if the two bodies stick together and move with common velocity v,then v=_____________

• m1u1-m2u2/m1+m2

• m1u1+m2u2/m1+m2

• m1*m2/m1m2

• m1u1*m2u2/m1m2

3.If the two bodies approach each other before collision,common velocity after collision is v=

• m1u1+m2u2/m1+m2

• m1u1-m2u2/m1+m2

• m1u2+m2u2/m1m2

• Both 2&3

4.when a body is in motion in the fluid,then there develops an opposing force,which opposes the motion of the body by the fluid.This force is called_____________

• Friction force

• Normal force

• Imaginary force

• Viscous drag

5.______________states that "For every action there exists equal and opposite reaction"

• Newton 2nd law

• Newton 1st law

• Newton 3rd law

• All the above

6.According to_______________,the total momentum of a system remains constant if no net external force acts on the system

• Newton law of motion

• Universal law of gravitation

• Law of conservation of momentum

• Lenz law

7.If a number of bodies collide with one another the total momentum of the bodies just before collision is _________to the total momentum after collision

• Unequal

• Zero

• Same

• Equal

8.If a number of bodies collide with one another the total momentum of the bodies just before collision is equal to the total momentum after collision

• m1u1+m2u2=m1v1+m2v2

• m1u2+m2u1/m1*m2

• m1u1-m2u2/m1-m2

• m1*m2/m1+m2

9.Unit of angular displacement is ________

• radian

• Candela

• ampere

• Newton

10.Symbol of angular displacement is__________

• m/s

• Cm

• rad

• N