DWARKA INTERNATIONAL SCHOOL

SECTOR-12, DWARKA, NEW DELHI-78

PHYSICS

Sample paperMAX MARKS: 70

Class -XITIME: 3 Hours

GENERAL INSTRUCTIONS:

1)All questions are compulsory.

2)Question numbers 1-8 are 1 mark questions.

3)Question numbers 9-18 are 2 marks questions.

4)Question numbers 19-27 are 3 marks questions.

5)Question numbers 28-30 are 5 mark questions.

6)There is no overall choice. However, internal choice has been provided in all the five marks questions. Only one option in such questions is to be attempted.

  1. Write S.I unit of luminous intensity and temperature?
  2. If V = at2 + bt3 where V is in m/s and t is in seconds. What are the units of a and b?
  3. Two masses in the ratio 1:2 are thrown vertically up with the same speed. What is the effect on time by the mass?
  4. Shipra went from her home to school 2.5km away. On finding her home closed she returned to her home immediately. What is her net displacement? What is the total distance covered by her?
  5. Friction is a self adjusting force. Justify.
  6. What provides the centripetal force to a car taking a turn on a level road?
  7. A spring is cut into two equal halves. How is the spring constant of each halfaffected?
  8. What is work done in holding a 15kg suitcase while waiting for a bus for 15minutes?
  9. If velocity, time and force were chosen the basic quantities, find the dimensionsof mass?
  10. Displacement of a particle is given by the expression x = 3t2 + 7t – 9, where x is inmeter and t is in seconds. What is acceleration?
  11. A balloon is ascending at the rate of 4.9m/s. A pocket is dropped from the balloonwhen situated at a height of 245m. How long does it take the packet to reach theground? What is its final velocity?
  12. What is the angle between two forces of 2N and 3N having resultant as 4N?
  13. What is the angle of projection at which horizontal range and maximum height areequal?
  14. Explain why, some leaves get detached when a tree is shaken vigorously?
  15. Give reason, why an atheist is made to land on sand or cushion?
  16. Why does a cyclist lean to one side, while going along curve?
  17. A light body and a heavy body have same linear momentum. Which one has greaterK.E.?
  18. A body of mass 3kg makes an elastic collision with another body at rest andcontinues to move in the original direction with a speed equal to one – third of itsoriginal speed. Fine the mass of the second body.
  19. The velocity V of water waves may depend on their wavelength, density ofwater and the acceleration due to gravity. Find relation between thesequantities by the method of dimension?
  20. A stone is dropped from the top of a cliff and is found to ravel 44.1m diving the last second before it reaches the ground. What is the height of the cliff? g = 9.8m/s2.
  21. Establish s = ut + at2 from velocity time graph for a uniform accelerated motion?
  22. Derive an equation for the path of a projectile fired parallel to horizontal.
  23. What is meant by coefficient of friction and angel of friction? Establish the relationbetween the two?
  24. A railway car of mass 20 tones moves with an initial speed of 54km/hr. Onapplying brakes, a constant negative acceleration of 0.3m/s2 is produced.

(i) What is the breaking force acting on the car?

(ii) In what time it will stop?

(iii) What distance will be covered by the car before if finally stops?

  1. A man weights 70 Kg. He stands on a weighting scale in a lift which is moving.

a)Upwards with a uniform speed of 10 m/s.

b)Downwards with a uniform acceleration of 5 m/s2.

c)Upwards with a uniform acceleration of 5 m/s2.

  1. Derive the expression for the potential energy stored in a spring?
  2. Show that for a freely falling body the sum of its kinetic energy and potentialenergy remains constant at all points during its fall?
  3. Velocity time graph of a moving particle is shown. Find the displacement (a) 0 – 4 s (b) 0 – 8s (c) 0- 12 s from the graph. Also write the differences between distance anddisplacement.

Or

State and prove the triangle law of vector addition.

  1. Derive an expression for acceleration of a body down a rough inclined plane.

OR

  1. Explain what is meant by coefficient of friction and angle of friction. Establish relation between the two.
  2. A force of 49 N is just able to move a block of wood weighting 10 Kg on a rough horizontal surface. Calculate the coefficient of friction and angle of friction.
  1. Define the kinetic and potential energy. Derive the expression of kinetic energy.

OR

Find the expression for the velocity of the two particles undergoing elastic collision in one dimension.