#### UNIT TEST LES 2

11th Standard

Reg.No. :
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Physics

Write objective

Time : 01:30:00 Hrs
Total Marks : 50
10 x 1 = 10
1. A ball is projected vertically upwards with a velocity v. It comes back to ground in time t. Which v-t graph shows the motion correctly?

(a)

(b)

(c)

(d)

2. If a particle executes uniform circular motion, choose the correct statement

(a)

The velocity and speed are constant

(b)

The acceleration and speed are constant.

(c)

The velocity and acceleration are constant.

(d)

The speed and magnitude of acceleration are constant.

3. The horizontal range and maximum height of a projectile are equal. The angle of projection is

(a)

$\theta =\tan ^{ -1 }{ (\frac { 1 }{ 4 } } )$

(b)

$\theta =\tan ^{ -1 }{ (4 } )$

(c)

$\theta =\tan ^{ -1 }{ (2 } )$

(d)

$\theta ={ 45 }^{ 0 }$

4. A stone is projected with speed of 50 m/s at an angle of 60° with the horizontal. The speed of the stone at highest point of trajectory is

(a)

75 m/s

(b)

25 m/s

(c)

50 m/s

(d)

cannot find

5. At the top of the trajectory of a projectile, the directions of its velocity and acceleration are

(a)

parallel to each other

(b)

antiparallel to each other

(c)

inclined to each other at an angle of 45°

(d)

perpendicular to each other

6. An object is projected at an angle of 45° with the horizontal. The horizontal range and the maximum height reached will be in the ratio

(a)

1 : 2

(b)

2 : 1

(c)

1 : 4

(d)

4 : 1

7. During projectile motion the quantities that remain unchanged are:

(a)

force and vertical velocity

(b)

acceleration and horizontal velocity

(c)

kinetic energy and acceleration

(d)

acceleration and momentum

8. The time of flight is __________ the time taken to attain the maximum height:

(a)

thrice

(b)

same

(c)

twice

(d)

four times

9. The path of the projectile, projected horizontally is:

(a)

hyperbola

(b)

parabola

(c)

straight line

(d)

circle

10. A particle is projected from the ground at an angle of θ with the horizontal with an initial speed of u. Time after which velocity vector of the projectile is perpendicular to the initial velocity.

(a)

u/g sinθ

(b)

u/g cosθ

(c)

2u/g sinθ

(d)

2u tanθ

11. 5 x 2 = 10

13. Define angular displacement and angular velocity.

14. Write down the kinematic equations for angular motion.

15. What is degree? Express 1 radian in degree.

16. Define non-uniform motion.

17. 6 x 3 = 18
18. Derive the relation between linear velocity and angular velocity.

19. Define uniform circular motion. Given some examples.

20. Derive an expression for the centripetal acceleration of a body moving in a circular path of radius 'r' with uniform speed.

21. In the cricket game, a batsman strikes the ball such that it moves with the speed 30ms-1 at an angle 30° with the horizontal as shown in the figure. The boundary line of the cricket ground is located at a distance of 75 m from the batsman? Will the ball go for a six? (Neglect the air resistance and take acceleration due to gravity g = 10m s-2).

22. Calculate the angle θ subtended by the two adjacent wooden spokes of a bullock cart wheel is shown in the figure'. Express the angle in both radian and degree.

23. A particle is in circular motion with an acceleration a = 0.2 rad s-2.
(a) What is the angular displacement made by the particle after 5 s?
(b) What is the angular velocity at t = 5 s? Assume the initial angular velocity is zero.

24. 4 x 5 = 20
25. A object is thrown with initial speed 5 m S-1 with an angle of projection 30$\gamma$ . What is the height and range reached by the particle?

26. A foot-ball player hits the ball with speed 20 m S-1 with angle 30° with respect to horizontal direction as shown in the figure. The goal post is at distance of 40 m from him. Find out whether ball reaches the goal post.

27. Shows that the path of horizontal projectile is a parabola and derive an expression for (i) Time of flight (ii) Horizontal range (iii) resultant relative and any instant (iv) speed of the projectile when it hits the ground?

28. Derive the relation between Tangential acceleration and angular acceleration.