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NLM

197 Questions Start Allen Test
All Exams Allen Objective Errorless
Q51 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
Two bodies of masses 5 kg and 8 kg are acted upon by the same force. If the acceleration of lighter body is $2 \, m/s^{2}$ , then the acceleration of the heavier body is :-
A.
$4 \, m/s^{2}$
B.
$2.5 \, m/s^{2}$
C.
$6.25 \, m/s^{2}$
D.
$1.25 \, m/s^{2}$
Q52 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
Action and reaction :- (For a given system)
(a) Act on the same object
(b) Have same direction
(c) Have different magnitudes
(d) Have non-zero resultant
A.
a, b, c
B.
b, c, d
C.
All of the above
D.
None of the above
Q53 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
Weight is defined as :-
A.
Force of attraction exerted by the earth
B.
Mass of a body
C.
Nature of a body
D.
None of these
Q54 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
A rider on horse falls back when horse starts running, all of a sudden because :-
A.
rider is taken back
B.
rider is suddenly afraid of falling
C.
inertia of rest keeps the upper part of body at rest while lower part of the body moves forward with the horse.
D.
none of the these
Q55 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
The force exerted by the floor of an elevator on the foot for a person standing there, is more than the weight of the person, if the elevator is A. Going up with increasing speed B. Going down with decreasing speed
A.
A is true but B is false
B.
A is false but B is true
C.
Both A and B are true
D.
Both A and B are false
Q56 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
A cork of mass 10 g is floating on water. The net force acting on the cork is :-
A.
10 N
B.
$10^{-3}\mathrm{N}$
C.
$10^{-2}\mathrm{N}$
D.
zero
Q57 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
Ten one-rupee coins are put on top of each other on a table. Each coin has a mass m. Which of the following statements is true? (counted from the bottom)
A.
The force on the $3^{rd}$ coin due to all the coins on its top is equal to 3mg (downwards).
B.
The force on the $6^{th}$ coin due to the $7^{th}$ coin is 4mg (downwards)
C.
The reaction of the $6^{th}$ coin on the $7^{th}$ coin is 3mg (upwards).
D.
The total force on the $10^{th}$ coin is 9mg (downwards)
Q58 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
Ten one rupees coins are put on top of each other on a table. Each coin has a mass 'm' kg., then the force on the $3^{rd}$ coin (counted from the bottom) due to all the coins on its top:-
A.
3 mg
B.
7 mg
C.
2 mg
D.
5 mg
Q59 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
The 50 kg homogeneous smooth sphere rests on the $30^{\circ}$ incline A and bears against the smooth vertical wall B. The contact forces at A and B are:-
A.
$\mathrm{N_A} = \frac{1000}{\sqrt{3}}\mathrm{N},\mathrm{N_B} = \frac{500}{\sqrt{3}}\mathrm{N}$
B.
$N_{A} = \frac{1000}{\sqrt{3}} N, N_{B} = \frac{1000}{\sqrt{3}} N$
C.
$N_{\mathrm{A}} = \frac{500}{\sqrt{3}} N, N_{\mathrm{B}} = \frac{500}{\sqrt{3}} N$
D.
$N_{\mathrm{A}} = \frac{500}{\sqrt{3}} N, N_{\mathrm{B}} = \frac{400}{\sqrt{3}} N$
Q60 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
The figure shows a horizontal force $\vec{F}$ acting on a block of mass m placed on an inclined plane (angle $\theta$ ). What is the normal reaction on the block?
A.
$\mathrm{mg}\sin \theta +\mathrm{F}\cos \theta$
B.
$\mathrm{mg}\sin \theta -\mathrm{F}\cos \theta$
C.
$\mathrm{mg}\cos \theta -\mathrm{F}\sin \theta$
D.
$\mathrm{mg}\cos \theta +\mathrm{F}\sin \theta$
Q61 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
Two forces of 6N and 3N are acting on the two blocks of 2kg and 1kg kept on frictionless floor. What is the force exerted on 2kg block by 1kg block?
A.
1N
B.
2N
C.
4N
D.
5N
Q62 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
Two blocks of masses 2 kg and 1 kg are in contact with each other on a frictionless table. When a horizontal force of 3.0 N is applied to the block of mass 1 kg the value of the force of contact between the two blocks is -
A.
2 N
B.
3 N
C.
5 N
D.
1 N
Q63 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
A person is standing in an elevator. In which situation he finds his weight more?
A.
when the elevator moves downward with constant velocity
B.
when the elevator moves downward with constant acceleration
C.
when the elevator moves upward with uniform velocity
D.
when the elevator moves downward with decreasing velocity
Q64 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
A man weighs 80 kg. He stands on a weighing scale in a lift which is moving downwards with a uniform acceleration of $5m/s^{2}$ . What would be the reading on the scale? (g = 10 m/ $s^{2}$ )
A.
Zero
B.
400 N
C.
800 N
D.
1200 N
Q65 Allen 3. FBD, NEWTON'S THIRD LAW MCQ
A man, of mass 60 kg, is riding in a lift. The ratio of the apparent weights of the man when the lift is accelerating upwards and downwards at $2 \, m/s^{2}$ is:-(Taking $g = 10 \, m/s^{2}$ )
A.
2 : 3
B.
1 : 1
C.
3 : 2
D.
none of these
Q66 Allen 4. EQUILIBRIUM FORCES MCQ
Two persons hold a rope of negligible weight tightly at its ends so that it is horizontal. A 15 kg weight is attached to the rope at the mid point which is now no longer remains horizontal. The minimum tension required to completely straighten the top is
A.
15 kg
B.
15/2 kg
C.
5 kg
D.
Infinitely large
Q67 Allen 4. EQUILIBRIUM FORCES MCQ
A boy of mass 40 kg is hanging from a horizontal branch of a tree. The tension in his arms is minimum when the angle between the arms is :-
A.
$0^{\circ}$
B.
$90^{\circ}$
C.
$120^{\circ}$
D.
$180^{\circ}$
Q68 Allen 4. EQUILIBRIUM FORCES MCQ
Find the ratio $\mathrm{T}_{1} / \mathrm{T}_{3}$ for the system shown in fig.
A.
$2:1$
B.
$1:4$
C.
$9:4$
D.
$3:1$
Q69 Allen 4. EQUILIBRIUM FORCES MCQ
A mass of 6 kg is suspended by a rope of length 2 m from a ceiling. A force of 60 N is applied in horizontal direction at the mid point of the rope. What is the angle between the rope and the vertical in equilibrium :-
A.
$\tan^{-1}\left(\frac{4}{5}\right)$
B.
$\tan^{-1}\left(\frac{5}{4}\right)$
C.
$\tan^{-1}\left(\frac{5}{6}\right)$
D.
$45^{\circ}$
Q70 Allen 4. EQUILIBRIUM FORCES MCQ
The pulleys and strings shown in the fig. are smooth and are of negligible mass. For the system to remain in equilibrium, the angle $\theta$ should be
A.
$0^{\circ}$
B.
$3 0 ^ {\circ}$
C.
$4 5 ^ {\circ}$
D.
$60^{\circ}$
Q71 Allen 4. EQUILIBRIUM FORCES MCQ
A uniform sphere of weight W and radius 3 m is being held by a string of length 2m attached to a frictionless wall as shown in the figure. The tension in the string will be :-
A.
5 W/4
B.
15 W/4
C.
15 W/16
D.
none of these
Q72 Allen 4. EQUILIBRIUM FORCES MCQ
A metal sphere is hung by a string fixed to a wall. The forces acting on the sphere are shown in fig. Which of the following statements is not correct?

(a)$\vec{R}+\vec{T}+\vec{W}=0$
(b)$ T^{2}=R^{2}+W^{2}$
(c) $T=R+W$
(d) $R=W\tan\theta$
A.
a
B.
b
C.
c
D.
d
Q73 Allen 5. CONNECTED BY STRINGS, PULLEY SYSTEM MCQ
Three identical blocks of mass m = 2kg are drawn by a force of 10.2 N on frictionless surface. The tension (in N) in the string between the blocks B and C is :-
A.
9.2
B.
8
C.
3.4
D.
9.8
Q74 Allen 5. CONNECTED BY STRINGS, PULLEY SYSTEM MCQ
Three masses $M_{1}$ , $M_{2}$ and $M_{3}$ are lying on a frictionless table. The masses are connected by massless threads as shown. The mass $M_{3}$ is pulled by a constant force F as shown. The tension in the thread between masses $M_{2}$ and $M_{3}$ is image.png
A.
$\frac{F}{2}$
B.
$\frac{F}{3}$
C.
$\frac{F}{4}$
D.
$\frac{F}{6}$
Q75 Allen 5. CONNECTED BY STRINGS, PULLEY SYSTEM MCQ
Three blocks are connected as shown in fig. on a horizontal frictionless table. If $M_{1} = 1$ kg, $M_{2} = 8$ kg, $M_{3} = 27$ kg and F = 36N, Then T' will be :-
A.
$18\mathrm{N}$
B.
$8\mathrm{N}$
C.
$35\mathrm{N}$
D.
$27\mathrm{N}$