Wednesday, 19 February 2020

PLUS ONE PHYSICS QUESTIONS AND ANSWERS

Chapter 5
           LAW OF MOTION

1. When we kick a stone ,we ge hurt due to which one of the  following properties it happens
Ans:- reaction

2. Passengers standing in a bus thrown outward  when the bus takes sudden turns.
This happens because of
Ans:- inertia

3. A body of mass 3kg moves with an acceleration of 2 m/s 2 . The change in momentum in one second is ...........

Ans:- force = change in momentum in one second 6 kg m/s

4. Unit of impulse is same as that

Ans:- impulse = change in momentum

5. Sliding friction is a self adjusting force  . State whether this statement true or False

Ans:- False.  Static friction is a self adjusting force

6. A bomb initially at rest explodes and the fragments move in different directions with different velocities. The total momentum of the fragments at any instance is

Ans:- conservation of momentum

7. A book is placed on the table. What is the angle between action of the book on the table and the reaction of the table on the book

Ans:- 180°

8. A body of mass 20 kg is sliding on a frictionless surface with velocity 1m/s .The force required to keep it moving with the same velocity 29 kg

Ans:- 0 N ( uniform velocity implies zero force)

9. A machine guns fires 120 bullet per minute . The mass of each bullet is
m and velocity is v.The force exerted on gun is

Ans :- 2 mv

10. If the radius of circular path particle is doubled without changing its angular velocity then the centripetal force on it is

Ans:- f is also doubled

11. What will be the force of friction suffered by a sphere  rolling without slipping  over a horizontal plane ?

Ans:- zero

12. A radioactive atom of mass 226 amu shoots out an alpha particle with a speed of 1.5 ×10 m/s . The speed of the radius atom is

Ans:- momentum of alpha particle + momentum of  rasidual atom = 0

13. An aircraft executes a horizontal loop at a speed of 720 km /hour with its wings banked at 15°. What is the radius of the loop

Ans:- 15. 23 km

14. State the law of conservation of momentum

Ans:-  it states that  the total momentum of an isolated system of interacting particle is conserved

15. State the Newton's law

Ans:- The rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction in which the force acts

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