#### MODEL QUESTION PAPER 5

11th Standard

Reg.No. :
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Physics

Use blue pen Only

Time : 01:30:00 Hrs
Total Marks : 40

Part A

Answer all the questions

7 x 1 = 7
1. Which of the following has the highest number of significant figures?

(a)

0.007 m2

(b)

2.64 x 1024kg

(c)

0.0006032 m2

(d)

6.3200 J

2. Identify the unit vector in the following

(a)

$\hat { i } +\hat { j }$

(b)

$\frac { \hat { i } }{ \sqrt { 2 } }$

(c)

$\hat { k } -\frac { \hat { j } }{ \sqrt { 2 } }$

(d)

$\frac { \hat { i } +\hat { j } }{ \sqrt { 2 } }$

3. A body of mass 30 kg climbs on a rope. The boy climbs up with an acceleration of 5 ms-2 What is the tension of a rope?

(a)

250 N

(b)

540 N

(c)

312 N

(d)

444 N

4. What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop?

(a)

$\sqrt{2gR}$

(b)

$\sqrt{3gR}$

(c)

$\sqrt{5gR}$

(d)

$\sqrt{gR}$

5. A bullet is fired from a rifle. If the rifle recoils freely the K.E of the rifle as compared to that of bullet is:

(a)

greater

(b)

equal

(c)

lesser

(d)

none of the above

6. When a mass is rotating in a plane about a fixed point, its angular momentum is directed along,

(a)

a line perpendicular to the plane of rotation

(b)

the line making an angle of 450 to the plane of rotation

(c)

(d)

tangent to the path

7. The centre of mass of a solid cone along the line from the centre of the base to the vertex is at:

(a)

one-fourth of the height

(b)

one-third of the height

(c)

one-fifth of the height

(d)

none of these

8. The angle between A i +j and B = i - j is

(a)

45°

(b)

90°

(c)

-45°

(d)

180°

9. Part B

Answer all the questions

7 x 2 = 14
10. A beam of metal has length, breadth and height as 4m, 3m and 5m respectively. Then what will be the volume of the metal beam? Express the result in SI unit system.

11. What are the factors the horizontal range directly depends?

12. Which is the greatest force among the three force $\bar { { F }_{ 1 } } ,\bar { { F }_{ 2 } } ,\bar { { F }_{ 3 } }$, shown below:

13. When is the exchange of energy maximum during an elastic collision?

14. Give examples where the centre of mass coincides with the geometrical centre of the body.

15. Write down the moment of inertia of a disc of radius R and mass m about an axis in its plane at a distance R/2 from its centre

16. If the Earth’s pull on the Moon suddenly disappears, what will happen to the Moon?

17. Part C

Answer all the questions

6 x 3 = 18
18. How will you measure the diameter of the Moon using parallax method?

19. The velocity of three particles A, B, C are given below. Which particle travels at the greatest speed?
$\vec {v_A}=3\hat i+5\hat j+2\hat k$
$\vec {V_B}=\hat i+2\hat j+3\hat k$
$\vec{V_C}=5\hat i+3\hat j+4\hat k$

20. A bomb of mass 30 kg, initially at rest explodes into three pieces of masses. m1 = m2 = 20 kg. If the kinetic energy of two pieces (m1 = m2) is 400 J. Calculate the kinetic energy of the third piece.

21. Define the following
a) Coefficient of restitution
b) Power
c) Law of conservation of energy
d) loss of kinetic energy in inelastic collision

22. A jester in a circus is standing with his arms extended on a turn table rotating with angular velocity $\omega$. He brings his arms closer to his body so that his moment of inertia is reduced to one third of the original value. Find his new angular velocity. [Given: There is no external torque on:the turn table in the given situation.]

23. How will you prove that Earth itself is spinning?