Physics MCQs Test Ch No. 5

CHAPTER # 5: CIRCULAR MOTION 1.       1 revolution: a)            57° b)            90° c)            180° d)    ...

CHAPTER # 5: CIRCULAR MOTION

1.      1 revolution:

a)           57°

b)           90°

c)           180°

d)           360°

2.      One radian is equal to.

a)      67.3^o

b)      57.3^o

c)      87.3^o

d)      60^o

3.      The SI unit of angular momentum is Js. It can also be expressed as:

a)           ⁻¹

b)           ^{2  −1}

c)           ^{2  −2}

d)           ^{−2  −1}

4.      The rate of change of angular displacement is called:

a)      Angular displacement

b)      Angular velocity

c)      Angular acceleration

d)      Torque

5.      Revolution/minute is the unit for

a)      Angular displacement

b)      Angular acceleration

c)      Angular velocity

d)      Time

6.      Time rate of change of angular velocity is called:

a)      Angular momentum

b)      Angular displacement

c)      Angular acceleration

d)      None of these

7.      The angular acceleration is produced by:

a)      Momentum

b)      Torque

c)      Pressure

d)      Power

8.      A particle is moving in a circle with constant speed. The direction of centripetal force will be:

a)      Along the tangent

b)      Along radius towards center

c)      Along radius away from center

d)      Changing with motion

9.    Moment of inertia is equal to:

a)           ²

b)        ^{2  2}

c)

d)           ²

10. Moment of inertia is measured in:

a)	2
b)	−2
c)
d)	/

11. The angular momentum is given by:

a)       mω

b)   ω × F

c)      r × F

d)   r × p

12. The period of a circular motion is given by. a) T = rV

b)   T = ww

c)   T = 2pw

d)   T = 2p/w

13. The direction of linear velocity of body moving in a circle is.

a) Along the axis of rotation b) Along the tangent

c) Directed towards the center d) Directed away from the center

14. The circumference subtends an angle.

a)   Radian

b)   2p radian

c)   p/2 radian

d)   4p radian

15. The relation between linear and angular

acceleration is.
a)				x
	a = a				r
b)		=		x
	a		r		a
c)		=
	a		a x		r
d)
	r =		a x		a

16.  When a body is whirled in a horizontal circle by means of a string the centripetal force is supplied by.

a)      Mass of a body

b)      Velocity of body

c)      Tension in the string

d)      None of these

17.  Centripetal force performs

a)      Maximum work

b)      Minimum work

c)      Negative work

d)      No work

18.   When a body moves in a circle of radius „r‟ with linear speed „V‟, its centripetal force is.

a)      mv / r²

b)      mv / r

c)      mv² / r

d)      mv² / r²

19.  The angular acceleration of a body is directed

a)      Towards the center of the circle

b)      Away from the center of the circle

c)      Along the tangent to the circle

d)      Along the axis of rotation

20.  The magnitude of the centripetal force on a mass m moving with angular speed in a circle of radius r is

a)          ²

b)          ²

c)                   

d)          ²

21.  The dimension of angular acceleration is:

a)           ⁻¹

b)           ⁻²

c)           ⁻³

d)          ⁻²

22.  A gymnast sitting on stool with his arms out stretched lowers his arms:

a)      The angular speed decreases

b)      The angular speed increases

c)      Neither increases nor decrease

d)      Both increases and decreases

23.   When torque acting on a system is zero, which of the following will be constant:

a)      Linear momentum

b)      Force

c)      Angular momentum

d)      Impulse

24.  The rotational K.E of any hoop of radius “r” is given by:

a)          ¹₂    ^{2  2}

b)          ¹₂  ^{2  2}

c)          ¹₂    ²

d)      None of these

25.  Unit of angular velocity in SI unit is:

a)           ./

b)           /

c)           /

d)           /

26.  Angular speed of daily rotation of earth is:

a)           2./

b)           ./

c)           4./

d)          7.3 × 10⁻⁵    ./

27.  The rotational K.E of a body is given by:

a)          ¹₂   ³

b)          ¹₃   ²

c)          ²

d)          ¹₂   ²

28.  The minimum velocity necessary to put a satellite into orbit is:

a)           7.1⁻¹

b)           7.3⁻¹

c)           7.9⁻¹

d)           8.9⁻¹

29.  The apparent weight of a man in an ascending lift moving with acceleration “a”:

a)      Increases

b)      Decreases

c)      Remains constant

d)      Becomes zero

30.   The apparent weight of a man in a lift moving down with an acceleration of

9.8   ⁻² is:

a)      Zero

b)      9.8 N

c)      19.6 N

d)      Infinity

 

31.  Which electromagnetic wave are used as medium in satellite communication system:

a)      Microwaves

b)      Radio waves

c)      Infrared waves

d)      Ultraviolet waves

32.  The minimum number of communication satellites required to cover the whole earth is:

a)      4

b)      3

c)      2

d)      5

33.   The critical speed of an artificial satellite is.

a)      6 Kms^-1

b)      8.1 Kms^-1

c)       7.9 Kms^-1

d)      8 ms^-1

34.  Geo-stationary satellite completes one rotation around earth in.

a)      3 hours

b)      6 hours

c)      12 hours

d)      24 hours

35.  In case planets the necessary acceleration is provided by.

a)      Gravitational force

b)      Frictional force

c)      Coulomb force

d)      Centripetal force

36.  The acceleration of a freely falling body is:

a)      Zero

b)      9.8 ms^-2

c)      32 ms^-2

d)      -9.8 ms^-2

37.  A man of weight W is standing on an elevator which is ascending with an acceleration a. The apparent weight of the man is.

a)      mg

b)      mg – ma

c)      mg + ma

d)      mg – ma

38.  If a body of mass 10 kg is allowed to fall freely, its weight becomes.

a)      zero

b)      98N

c)      9.8N

d)      10N

39.  Pull of earth on a mass of 20 kg on the surface of the earth is

a)      20 N

b)      196 N

c)      19.6 N

d)      1960 N

Q. No.	Ans.	Q. No.	Ans.	Q. No.	Ans.
1	d	14	b	27	d
2	b	15	c	28	c
3	b	16	c	29	a
4	b	17	d	30	a
5	c	18	c	31	a
6	c	19	d	32	c
7	b	20	d	33	c
8	b	21	b	34	d
9	d	22	b	35	a
10	a	23	c	36	b
11	d	24	a	37	c
12	d	25	a	38	a
13	b	26	d	39	b