#### Motion of System of Particles and Rigid Bodies Model Question Paper

11th Standard

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Physics

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. A couple produces,

(a)

pure rotation

(b)

pure translation

(c)

rotation and translation

(d)

no motion

2. The angular momentum of a rotating body is doubled, its K.E. of rotation becomes

(a)

Two times

(b)

Four times

(c)

Halved

(d)

Eight times

3. A particle undergoes uniform circular motion. The angular momentum of the particle remain conserved about,

(a)

the center point of the circle.

(b)

the point on the circumference of the circle.

(c)

any point inside the circle.

(d)

any point outside the circle

4. The speed of a solid sphere after rolling down from rest without sliding on an inclined plane of vertical height his,

(a)

$\sqrt \frac{4}{3}gh$

(b)

$\sqrt \frac{10}{7}gh$

(c)

$\sqrt{2gh}$

(d)

$\sqrt \frac{1}{2}gh$

5. Two blocks of masses 20 kg and 5 kg are connected by a spring of negligible mass and placed on a frictionless horizontal surface. An impulse gives a velocity of 15 mls to the heavier block in the direction of lighter block. The velocity of centre of mass is

(a)

22 ms-1

(b)

30 ms-1

(c)

12 ms-1

(d)

15 ms-1

6. 5 x 2 = 10
7. What is rigid body?

8. When does the body have precession?

9. What is meant by rolling friction?

10. Three identical solid spheres move down through three inclined planes A, B and C all same dimensions. A is without friction, B is undergoing pure rolling and C is rolling with slipping. Compare the kinetic energies EA' EB and Ec at the bottom.

11. A force of $(4\hat{i}-3\hat{j}+5\hat{k})$ N is applied at a point whose position vector is $(7\hat{i}+4\hat{j}-2\hat{k})$m.Find the torque of force about the origin.

12. 5 x 3 = 15
13. What is equilibrium?

14. How do you distinguish between stable and unstable equilibrium?

15. Mention any two physical significance of moment of inertia

16. Write the comparison of translational and rotational quantities?

17. Distinguish between internal and external forces.

18. 4 x 5 = 20
19. Explain the method to find the center of gravity of a irregularly shaped lamina.

20. Derive the expression for moment ofinertia of a uniform disc about an axis passing through the center and perpendicular to the plane.

21. Discuss the motion of a disc rolling on a level surface.

22. The moment of inertia of a thin rod of mass 'M' and length 'I' about an axis passing through its centre is $\frac { M{ l }^{ 2 } }{ 12 }$. Calculate the moment of inertia about a parallel axis through end of rod.