Q426
Allen
CONNECTED BY STRINGS, PULLEY SYSTEM
MCQ
In the fig. mass m = 10 kg then in order to keep it at rest, the value of mass M will be:
A.
10 kg
B.
5 kg
C.
20 kg
D.
40 kg
Q427
Allen
CONNECTED BY STRINGS, PULLEY SYSTEM
MCQ
A block of mass 4 kg is suspended through two light spring balances A and B in parallel. Then A and B will read respectively.
A.
4 kg and zero kg
B.
zero kg and 4 kg
C.
4 kg and 4 kg
D.
2 kg and 2 kg
Q428
Allen
CONNECTED BY STRINGS, PULLEY SYSTEM
MCQ
Two masses $m_{1}$ and $m_{2}$ are joined by a spring as shown. The system is dropped to the ground from a certain height. The spring will be :-
A.
Stretched when $m_{2} > m_{1}$
B.
compressed when $m_{2} < m_{1}$
C.
neither compressed nor stretched only when $m_{1} = m_{2}$
D.
neither compressed nor stretched regardless of the values of $m_{1}$ and $m_{2}$ .
Q429
Allen
CONNECTED BY STRINGS, PULLEY SYSTEM
MCQ
Two masses of 1 kg and 2 kg respectively are connected by a massless spring as shown in figure. A force of 20 N acts on the 2 kg mass at the instant when the 1 kg mass has an acceleration of $10 \, ms^{-2}$ towards right, the acceleration of the 2 kg mass is:-
A.
$$<br />
2 \mathrm{ms} ^ {- 2}<br />
$$
B.
$$<br />
5 \mathrm{ms} ^ {- 2}<br />
$$
C.
$$<br />
10 \mathrm{ms} ^ {- 2}<br />
$$
D.
$$20<br />
\mathbf {m s} ^ {- 2}<br />
$$
Q430
Allen
CONNECTED BY STRINGS, PULLEY SYSTEM
MCQ
Two masses of 20 kg and 30 kg respectively are connected by a massless spring as shown in the figure. A force of 200 N acts on the 30 kg mass. At the instant shown the 20 kg mass has an acceleration $2 \, m/s^{2}$ rightwards. What is the acceleration of 30 kg mass?
A.
Zero
B.
$5.3\mathrm{m / s^2}$
C.
$4\mathrm{m / s^2}$
D.
$8\mathrm{m / s^2}$
Q431
Allen
CONNECTED BY STRINGS, PULLEY SYSTEM
MCQ
A body of mass 5kg is suspended by a spring balance on an inclined plane as shown in figure. The spring balance measure
A.
50 N
B.
25 N
C.
500 N
D.
10 N
Q432
Allen
CONNECTED BY STRINGS, PULLEY SYSTEM
MCQ
A man is standing at a spring platform. Reading of spring balance is 60 kg-wt. If the man jumps off from the platform, then reading of spring balance
A.
First increases then decreases to zero
B.
Decreases
C.
Increases
D.
Remains same
Q433
Allen
FRAME OF REFERENCE
MCQ
In Newton's second Law $\vec{\mathrm{F}} = \mathrm{m}\vec{\mathrm{a}}$ (for constant mass m), $\vec{\mathrm{a}}$ is the acceleration of the mass m with respect to
A.
any observer
B.
any inertial observer
C.
an observer at rest only
D.
an observer moving with uniform speed only
Q434
Allen
FRAME OF REFERENCE
MCQ
A frame will be inertial, if it moves with respect to another inertial frame with a constant :-
A.
Linear velocity
B.
Angular velocity
C.
Linear acceleration
D.
All of the above
Q435
Allen
FRAME OF REFERENCE
MCQ
A small sphere of mass m is suspended by a string from the ceiling of a car. If the car begins to move with a constant acceleration $\frac{g}{2}$ , then the tension in the string is :-
A.
mg
B.
$\frac{3}{2}$ mg
C.
$\frac{\sqrt{5}}{2}$ mg
D.
$\frac{mg}{2}$
Q436
Allen
FRAME OF REFERENCE
MCQ
A boy sitting on the upper berth in the compartment of an accelerated train, which is just left the railway station, drops an apple aiming at the open hand of his brother vertically below his hands at a distance of about 2 m. The apple will fall :-
A.
In the hand of his brother
B.
Slightly away from the hands of his brother in the direction of motion of the train
C.
Slightly away from the hands of his brother in the direction opposite to the direction of motion of the train
D.
None of the above
Q437
Allen
FRAME OF REFERENCE
MCQ
The force exerted by a person on the floor of an elevator is less than the weight of the person if the elevator is :-
(a) Going up and slowing down
(b) Going up and speeding up
(c) Going down and slowing down
(d) Going down and speeding up
(a) Going up and slowing down
(b) Going up and speeding up
(c) Going down and slowing down
(d) Going down and speeding up
A.
a, c
B.
b, c
C.
a, d
D.
b, d
Q438
Allen
FRAME OF REFERENCE
MCQ
Two equal masses are kept on the pans of a simple balance in a lift accelerating upward. Then
A.
Pans will remain at the same level.
B.
Nothing can be said as data is incomplete
C.
Left side pan will lower down.
D.
Right side pan will lower down.
Q439
Allen
FRAME OF REFERENCE
MCQ
The ratio of weights of a man in a lift moving with acceleration 'a' in upward direction and moving with acceleration 'a' in downward direction is 3:1. Then the value of a is:
A.
$\frac{g}{3}$
B.
$\frac{g}{2}$
C.
$\frac{g}{5}$
D.
$\frac{4}{3}g$
Q440
Allen
FRAME OF REFERENCE
MCQ
A man weighing 100 kg carries a load of 10 kg on his head. He jumps from a tower with the load on his head. What will be the weight of the load as experienced by the man?
A.
zero
B.
10 kg
C.
slightly more than 10 kg
D.
110 kg
Q441
Allen
FRAME OF REFERENCE
MCQ
The elevator shown in figure is descending, with a retardation of $2 \, m/s^{2}$ . The mass of the block A is 0.5 kg. The force exerted by the block A on the block B is :
A.
$2\mathrm{N}$
B.
$4\mathrm{N}$
C.
$6\mathrm{N}$
D.
$8\mathrm{N}$
Q442
Allen
FRAME OF REFERENCE
MCQ
Drums of oil are carried in a moving truck. Suddenly breaks are applied on the truck then the surface of the oil in the drum will -
A.
Remain unaffected
B.
Rise in the forward direction
C.
Rise in the backward direction
D.
Nothing is certain
Q443
Allen
FRAME OF REFERENCE
MCQ
A block of mass m is placed on a smooth wedge of inclination $\theta$ . The whole system is accelerated horizontally so that the block does not slip on the wedge. The force exerted by the wedge on the block (g is acceleration due to gravity) will be :-
A.
mg sin $\theta$
B.
mg
C.
mg/cos $\theta$
D.
mg cos $\theta$
Q444
Allen
FRAME OF REFERENCE
MCQ
A body kept on a smooth inclined plane of inclination 1 in x will remain stationary relative to the inclined plane if the plane is given a horizontal acceleration equal to:
A.
$\sqrt{x^{2}-1}g$
B.
$\frac{\sqrt{x^{2}-1}}{x}g$
C.
$\frac{gx}{\sqrt{x^{2}-1}}$
D.
$\frac{g}{\sqrt{x^{2}-1}}$
Q445
Allen
FRAME OF REFERENCE
MCQ
An object of mass 2 kg moving with constant velocity $10\hat{i}$ m/s is seen in a frame moving with constant velocity $10\hat{i}$ m/s. The value of 'pseudo force' acting on object in this frame will be :-
A.
20 N
B.
0 N
C.
10 N
D.
2 N
Q446
Allen
FRAME OF REFERENCE
MCQ
A triangular wedge of mass M rests on a smooth surface as shown in figure. A cubical block of mass m rests on the inclined surface of wedge. If all surfaces are frictionless, the horizontal force that must be applied to the wedge so as to keep the block stationary relative to the wedge is :-
A.
Mg tan30Ā°
B.
mg tan30Ā°
C.
(M+m)g tan30Ā°
D.
(M+m)g cos30Ā°
Q447
Allen
FRAME OF REFERENCE
MCQ
What is the mechanical advantage of single fixed pulley?
A.
1
B.
2
C.
0.5
D.
4
Q448
Allen
FRAME OF REFERENCE
MCQ
The force required to lift a 400 kg wt is 80 kg wt then the mechanical advantage is :-
A.
8
B.
10
C.
5
D.
4
Q449
Allen
FRICTION
MCQ
The coefficient of static friction between two surfaces depend on
A.
the normal reaction on the surface
B.
the shape of the surface in contact
C.
the area of contact
D.
None of the above
Q450
Allen
FRICTION
MCQ
A girl horizontally press her physics text book against a rough vertical wall with her hand. The direction of the frictional force on the book exerted by the wall is :-
A.
downwards
B.
upwards
C.
out from the wall
D.
into the wall