SESSION ENDING EXAMINATION – (2013-2014) Physics (Set 1) CBSE CLASS – XI

Time: 3 Hrs. M.M: 70

General Instructions:

1. Question 1 to 5 one mark.
2. Question 6 to 10 each two mark.
3. Question 11 to 22 each three mark.
4. Question 23 is value based question and carry four marks.
5. Questions 24 to 26 each five mark.

Write the dimension and SI unit of linear momentum.

1. What does the slope of velocity-time graph represent.
2. Give the magnitude and direction of net force acting on
3. A drop of rain falling down with constant speed
4. A cork of mass 10g floating on water.
5. Name the physical quantity which is expressed as 'the dot product of force and velocity'. Is it scalar or a vector quantity?
6. Is it necessary that the centre of mass of a body should always lie inside the body? Justify your answer.
7. In which of the following examples of motion can the body be considered approximately a point object:
8. A railway carriage moving without jerks between two stations.
9. A monkey sitting on the top of a man cycling smoothly on a circular track.
10. A spinning cricket ball that turns sharply on hitting the ground, and
11. Tumbling beaker that has slipped off the edge of a table?
12. (a) Define relative error.

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1. The error in the measurement of radius of sphere is 2%. What would be the error in the volume of the sphere?
2. State the law of conservation of linear momentum. Derive it from the Newton's second law of motion.

OR

Define coefficient of limiting friction. A body slides down an incline plane having friction. Indicate the directions of frictional force and the reaction of the plane on the body.

1. A body of mass m is raised to a height h from the surface of the earth where the

acceleration due to gravity on the surface of the earth where the acceleration due to gravity on the surface of the earth. Prove that the loss in weight due to variation of g is approximately 2mgh/R. Where R is the radius of earth and H<<R.

1. The escape velocity on earth is 11.2 km/s. What will be its value on a planet having double the radius and eight times the mass of earth?
2. Explain why:
3. It is easier to pull a lawn mower than to push it.
4. A cricketer moves his hands backwards while holding a catch.
5. The outer rail of a curved railway track is generally raised over the inner.
6. The displacement (in metre) of a particle moving along x-axis is given by <math>x = 18t + 5t^2</math>. Calculate:
7. The instantaneous velocity at t = 2s.

(b) Average velocity between <math>t = 2s</math> and <math>t = 3s</math>.

1. Instantaneous acceleration

1. Rain is falling vertically with a speed of <math>30 m_s^{-1}</math>. A woman rides a bicycle with a speed of

<math>10_{ms}^{-1}</math> in north to south direction. What is the relative velocity of rain with respect to the woman? What is the direction in which she should hold her umberalla to protect herself?

1. The velocity 'v' of water waves depends on the wavelength '¿', density of water 'p' and

the acceleration due to gravity 'g'. Deduce by method of dimensions the relationship between these quantities. 2/4