AFMC 2012
Q51
Objective
5. Medical entrances' gallery
MCQ
A machine gun fires a bullet of mass 40 g with a velocity $1200 \, ms^{-1}$ . The man holding it can exert a maximum force of 144 N on the gun. How many bullets can be fired per second at the most?
A.
Only one
B.
Three
C.
Can fire any number of bullets
D.
$144 \times 48$
JCECE 2012
Q52
Objective
5. Medical entrances' gallery
MCQ
A monkey of mass 25 kg is holding a vertical rope. The rope does not break, if a body of mass 30 kg is suspended from it, but the rope breaks, if the mass of the body suspended with the rope exceeds 30 kg. What will be the maximum acceleration with which the monkey can climb up along the rope? (Take, $g = 10 \, ms^{-2}$ )
A.
$2 \, ms^{-2}$
B.
$25 \, ms^{-2}$
C.
$3 \, ms^{-2}$
D.
$4 \, ms^{-2}$
JCECE 2012
Q53
Objective
5. Medical entrances' gallery
MCQ
A body of weight 50 N placed on a horizontal surface is just moved by a force of 282 N. The frictional force and normal reaction are
A.
$2\mathrm{N},3\mathrm{N}$
B.
$5\mathrm{N},6\mathrm{N}$
C.
$10\mathrm{N},15\mathrm{N}$
D.
$20\mathrm{N},30\mathrm{N}$
RPMT 2011
Q54
Objective
5. Medical entrances' gallery
MCQ
Diwali rocket is ejecting 50 g of gases/s at a velocity of $400 \, ms^{-1}$ . The accelerating force on the rocket will be
A.
22 dyne
B.
20 N
C.
20 dyne
D.
100 N
AMU 2011
Q55
Objective
5. Medical entrances' gallery
MCQ
A rocket of mass 1000 kg is to be projected vertically upwards. The gases are exhausted vertically downwards with velocity $100 \, ms^{-1}$ with respect to the rocket. What is the minimum rate of burning of fuel, so as to just lift the rocket upwards against the gravitational attraction?
(Take, $g = 10 \, ms^{-2}$ )
A.
$50 \, kg s^{-1}$
B.
$100 \, kg s^{-1}$
C.
$200 \, kg s^{-1}$
D.
$400 \, kg s^{-1}$
DUMET 2011
Q56
Objective
5. Medical entrances' gallery
MCQ
In a non-inertial frame, the second law of motion is written as
A.
$\mathbf{F} = m\mathbf{a}$
B.
$\mathbf{F} = m\mathbf{a} + \mathbf{F}_p$
C.
$\mathbf{F} = m\mathbf{a} - \mathbf{F}_p$
D.
$\mathbf{F} = 2m\mathbf{a}$ where, $\mathbf{F}_p$ is pseudo force while $\mathbf{a}$ is the acceleration of the body relative to the non-inertial frame.
AMU 2011
Q57
Objective
5. Medical entrances' gallery
MCQ
A man of mass 60 kg is riding in a lift. The weight of the man when the lift is accelerating upwards and downwards at $2 \, ms^{-2}$ are respectively (Take, $g = 10 \, ms^{-2}$ )
A.
720 N and 480 N
B.
480 N and 720 N
C.
600 N and 600 N
D.
None of these
DUMET 2011
Q58
Objective
5. Medical entrances' gallery
MCQ
An object is moving on a plane surface with uniform velocity $10 \, ms^{-1}$ in presence of a force 10 N. The frictional force between the object and the surface is
A.
1 N
B.
- 10 N
C.
10 N
D.
100 N
Q59
Objective
1. Taking it together
MCQ
A metre scale is moving with uniform velocity. This implies
A.
the force acting on the scale is zero, but a torque about the centre of mass can act on the scale
B.
the force acting on the scale is zero and the torque acting about centre of mass of the scale is also zero
C.
the total force acting on it need not be zero but the torque on it is zero
D.
Neither the force nor the torque need to be zero
Q60
Objective
1. Taking it together
MCQ
Conservation of momentum in a collision between particles can be understood from
A.
conservation of energy
B.
Newton's first law only
C.
Newton's second law only
D.
Both Newton's second and third law
Q61
Objective
1. Taking it together
MCQ
If the elevator in the shown figure is moving upwards with constant acceleration $1 \, ms^{-2}$ , the tension in the string connected to block A of mass 6 kg would be (Take, $g = 10 \, ms^{-2}$ )
A.
60 N
B.
66 N
C.
54 N
D.
42 N
Q62
Objective
1. Taking it together
MCQ
A block is placed on the top of a smooth inclined plane of inclination $\theta$ kept on the floor of a lift. When the lift is descending with a retardation a, the block is released. The acceleration of the block relative to the incline is
A.
$g \sin \theta$
B.
$a \sin \theta$
C.
$(g - a) \sin \theta$
D.
$(g + a) \sin \theta$
Q63
Objective
1. Taking it together
MCQ
A cricket ball of mass 150 g has an initial velocity $\mathbf{u} = (3\hat{\mathbf{i}} + 4\hat{\mathbf{j}}) \, \mathrm{ms}^{-1}$ and a final velocity $\mathbf{v} = -(3\hat{\mathbf{i}} + 4\hat{\mathbf{j}}) \, \mathrm{ms}^{-1}$ , after being hit. The change in momentum (final momentum – initial momentum) is (in kg·ms $^{-1}$ )
A.
zero
B.
$-(0.45\hat{\mathbf{i}} + 0.6\hat{\mathbf{j}})$
C.
$-(0.9\hat{\mathbf{i}} + 1.2\hat{\mathbf{j}})$
D.
$-5(\hat{\mathbf{i}} + \hat{\mathbf{j}})\hat{\mathbf{i}}$
Q64
Objective
1. Taking it together
MCQ
In the previous question (5), the magnitude of the momentum transferred during the hit is
A.
zero
B.
$0.75 \, kg \cdot ms^{-1}$
C.
$1.5 \, kg \cdot ms^{-1}$
D.
$14 \, kg \cdot ms^{-1}$
Q65
Objective
1. Taking it together
MCQ
A block of mass m is placed on a smooth plane inclined at an angle $\theta$ with the horizontal. The force exerted by the plane on the block has a magnitude
A.
mg
B.
mg sec $\theta$
C.
mg cos $\theta$
D.
mg sin $\theta$
Q66
Objective
1. Taking it together
MCQ
A block has been placed on an inclined plane. The slope angle $\theta$ of the plane is such that the block slides down the plane at a constant speed. The coefficient of kinetic friction is equal to
A.
$\sin\theta$
B.
$\cos\theta$
C.
g
D.
$\tan\theta$
Q67
Objective
1. Taking it together
MCQ
A body is projected up a $45^{\circ}$ rough incline. If the coefficient of friction is 0.5, then the retardation of the block is
A.
$\frac{g}{2\sqrt{2}}$
B.
$\frac{g}{\sqrt{2}}$
C.
$\frac{3g}{2\sqrt{2}}$
D.
$\frac{g}{2}$
Q68
Objective
1. Taking it together
MCQ
A rope of length L and mass M is hanging from a rigid support. The tension in the rope at a distance x from the rigid support is
A.
Mg
B.
$\left(\frac{L-x}{L}\right)Mg$
C.
$\left(\frac{L}{L-x}\right)Mg$
D.
$\frac{x}{L}Mg$
Q69
Objective
1. Taking it together
MCQ
Consider the shown arrangement. Assume all surfaces to be smooth. If N represents magnitudes of normal reaction between block and wedge, then acceleration of M along horizontal is equal to
A.
$\frac{N\sin\theta}{M}$ along + ve $X$ -axis
B.
$\frac{N\cos\theta}{M}$ along -ve $X$ -axis
C.
$\frac{N\sin\theta}{M}$ along -ve $X$ -axis
D.
$\frac{N\sin\theta}{m + M}$ along -ve $X$ -axis
Q70
Objective
1. Taking it together
MCQ
In the above problem, normal reaction between ground and wedge will have magnitude equal to
A.
$N \cos \theta + Mg$
B.
$N \cos \theta + Mg + mg$
C.
$N \cos \theta - Mg$
D.
$N \sin \theta + Mg + mg$
Q71
Objective
1. Taking it together
MCQ
A block of mass m is at rest on an inclined plane which is making angle $\theta$ with the horizontal. The coefficient of friction between the block and plane is $\mu$ . Then, frictional force acting between the surfaces is
A.
$\mu mg$
B.
$\mu mg\sin \theta$
C.
$\mu (mg\sin \theta -mg\cos \theta)$
D.
$mg\sin \theta$
Q72
Objective
1. Taking it together
MCQ
If a body loses half of its velocity on penetrating 3 cm in a wooden block, then how much will it penetrate more before coming to rest?
A.
1cm
B.
2 cm
C.
3 cm
D.
4 cm
Q73
Objective
1. Taking it together
MCQ
An insect crawls up a hemispherical surface very slowly (see the figure). The coefficient of friction between the insect and the surface is 1/3. If the line joining the centre of the hemispherical surface to the insect makes an angle $\alpha$ with the vertical, the maximum possible value of $\alpha$ is given by
A.
$\cot \alpha = 3$
B.
$\tan \alpha = 3$
C.
$\sec \alpha = 3$
D.
$\csc \alpha = 3$
Q74
Objective
1. Taking it together
MCQ
A hockey player is moving northward and suddenly turns westward with the same speed to avoid an opponent. The force that acts on the player is
A.
frictional force along westward
B.
muscle force along southward
C.
frictional force along south-west
D.
muscle force along south-west
Q75
Objective
1. Taking it together
MCQ
A car of mass m starts from rest and acquires a velocity along east $\mathbf{v} = v\hat{\mathbf{i}}(v > 0)$ in two seconds.
Assuming the car moves with uniform acceleration, the force exerted on the car is
A.
$\frac{mv}{2}$ eastward and is exerted by the car engine
B.
$\frac{mv}{2}$ eastward and is due to the friction on the tyres exerted by the road
C.
more than $\frac{mv}{2}$ eastward exerted due to the engine and overcomes the friction of the road
D.
$\frac{mv}{2}$ exerted by the engine
