PHYSICS CLASS 11 - ASSIGNMENT 6 - LAWS OF MOTION

 CLASS 11 

LAWS OF MOTION

ASSIGNMENT 6

1. Define force.  State the various effects produced by force.

2. State Aristotle's law of motion.

3. State Galileo's law of inertia.

4. What is inertia?

5. Write the different types of inertia and give one example of each.

6. Define momentum.  Is it a scalar or vector quantity?

7. State Newton's laws of motion.

8. State and explain Newton's first law of motion.

9. Give a qualitative definition of force.

10.  Why is Newton's first law of motion also called as law of inertia?

11. Give one example from daily life that illustrates Newton's first law of motion based on (i) inertia of rest (ii) inertia of motion (iii) inertia of direction.

12. Explain how Newton's second law of motion gives a quantitative definition of force.

13. Define inertial mass of a body.

14. Is any external force required to keep a body in uniform motion?

15. Write the dimensions of force.  Is force a scalar or vector quantity?

16. Is it correct to say that the second law of motion is the real law of motion?

17. Name and define the various absolute and gravitational units of force.

18. Express Newton's second law of motion in component form.  Also give its significance.

19.  Give four important implications of Newton's second law of motion.

20. What is meant by 'Newton's second law is a local relation'? Explain with an example.

21. How does Newton's second law of motion lead to the concept of inertial mass?

22. Define impulsive forces.  Give examples.

23. Define impulse of a force.  Give its units and dimensions.

24. State and prove impulse - momentum theorem.

25. Give any three practical examples from daily life which make use of the concept of impulse.

26.  State and explain Newton's third law of motion.

27. Give some real life examples which illustrate Newton's third law of motion.

28. Explain how a horse is able to pull a cart.

29. Show that Newton's second law of motion is the real law of motion.

30. Write the relation between newton and dyne.

31. State the law of conservation of linear momentum and derive it from Newton's second law of motion.

32. Derive the law of conservation of linear momentum from Newton's third law of motion.

33. Derive Newton's third law of motion from the law of conservation of momentum.

34. Give some examples from daily life which illustrate the law of conservation of linear momentum.

35. Find the number of dynes in one Newton.

36. A force of 72 dyne is inclined to the horizontal at an angle of 60° .  Find the acceleration in a mass of 9 g, which moves in a horizontal direction.

37.  A particle of mass m moves along x-axis such that its position coordinate at any instant t is x = at⁴ - bt³ + ct,  where a,b and c are constants.  What is the force acting on the particle at any instant t?

38. Forces of 5√2 N and 6√2 N are acting on a body of mass 1000 kg at an angle of 60° to each other.  Find the acceleration, distance covered and the velocity of the mass after 10 s.

39. A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of 15 m/s.  How long does the body take to stop?

40.  A constant force acting on a body of mass 3 kg changes its speed from 2 m/s to 3.5 m/s in 25 s.  The direction of motion of the force remains unchanged.  What is the magnitude and the direction of the force?

41. A body of mass 5 kg is acted upon by two perpendicular forces of 8 N and 6 N.  Give the magnitude and direction of the acceleration of the body.

42.  Give the magnitude and direction of the net force actin on (i)  a kite held stationary in the sky.

(ii) a cork of mass 10 g floating on water.

43. Two masses 8 kg and 12 kg are connected at the two ends of a a light inextensible string that goes over a frictionless pulley.  Find the acceleration of the masses and the rtension in the string when the masses are released.

44. What do you mean by banking of a curved road? Determine the angle of banking so that the wear and tear of the car tyres can be minimised.

45. Explain how a vehicle is able to go round a level curved road. Find the maximum speed with which it can negotiate this road.

46. Define friction, static, limiting and Kinetic frictions.

47. State the laws of friction.

48. Define the two types of Kinetic frictions.

49. What is coefficient of friction?

50. A body rolled on ice with a velocity of 8 m/s comes to rest after travelling 4 m. Find the coefficient of friction.

51. The coefficient of friction between the ground and the wheels of a car moving on a horizontal road is 0.5. If the car starts from rest, what is the minimum distance in which it can acquire a speed of 72 km/h. Take g=10m/s

52. Two masses M and m are connected at the two ends of an inextensible string. The string passes over a smooth frictionless pulley. Find the acceleration of the masses and the tension in the string. Given M >m.