Q.1
Which one of the following is not used to reduce friction . [Kerala (Engg.)]
  • a) Oil
  • b) Sand
  • c)Ball bearings
  • d)Graphite
Q.2
A bullet of mass M is fired with velocity of 50m/s at an angle of θ with the horizontal. At the highest point of its trajectory, it collides head on with a bob of mass 3M suspended by a massless string of length (10/3) m and gets embedded in the bob. After the collision, the string moves to an angle of 120o. What is the angle θ
ch-4_que_no-305_img_no1.png
  • a)cos⁻¹ (4/5)
  • b) cos⁻¹(5/4)
  • c)sin⁻¹(4/5)
  • d)sin⁻¹(5/4)
Q.3
A diwali rocket is ejecting 0.05 kg of gases per second at a velocity of 400 m/sec. The accelerating force on the rocket is. [NCERT 1979; DPM]
  • a) 20 dynes
  • b) 22 dynes
  • c)20 N
  • d)1000 N
Q.4
An automobile travelling with a speed of 60km/h can brake to stop within a distance of 20 m. If the car is going twice as fast, i.e. 120 km/h, the stopping distance will be . [AIEEE 2004]
  • a)20 m
  • b)60 m
  • c)40 m
  • d)80 m
Q.5
A cork is submerged in water by a spring attached to the bottom of a pail. When the pail is kept in a elevator moving with an acceleration downwards, the spring length . [EAMCET (Engg.)]
  • a) Increases
  • b) Remains unchanged
  • c) Decreases
  • d) Data insufficient
Q.6
If a person with a spring balance and a body hanging from it goes up and up in an aeroplane, then the reading of the weight of the body as indicated by the spring balance will . [AIIMS 1998; JIP]
  • a)Go on increasing
  • b)First increase and then decrease
  • c)Go on decreasing
  • d)Remain the same
Q.7
An object will continue moving uniformly until . [CPMT 1975]
  • a)The resultant force acting on it begins to decrease
  • b) The resultant force is at right angle to its rotation
  • c)The resultant force on it is zero
  • d)The resultant force on it is increased continuously
Q.8
A rocket of mass 1000 kg exhausts gases at a rate of 4 kg/sec with a velocity 3000 m/s. The thrust developed on the rocket is. [Orissa JEE 2005]
  • a) 12000 N
  • b) 800 N
  • c) 120 N
  • d) 200 N
Q.9
In doubling the mass and acceleration of the mass, the force acting on the mass with respect to the previous value
  • a)Decreases to half
  • b)Increases two times
  • c)Remains unchanged
  • d)Increases four times
Q.10
A body, whose momentum is constant, must have constant . [AIIMS 2000]
  • a)Force
  • b)Acceleration
  • c)Velocity
  • d)All of these
Q.11
A cold soft drink is kept on the balance. When the cap is open, then the weight. [AFMC 1996]
  • a)Increases
  • b) First increases then decreases
  • c)Decreases
  • d)Remains same
Q.12
A cricket ball of mass 250 g collides with a bat with velocity 10 m/s and returns with the same velocity within 0.01 second. The force acted on bat is. [CPMT 1997]
  • a) 25 N
  • b) 250 N
  • c) 50 N
  • d) 500 N
Q.13
A block of mass 5kg is moving horizontally at a speed of 1.5 m/s. A perpendicular force of 5N acts on it for 4 sec. What will be the distance of the block from the point where the force started acting. [Pb. PMT 2002]
  • a)10 m
  • b)6 m
  • c)8 m
  • d)2 m
Q.14
A person sitting in an open car moving at constant velocity throws a ball vertically up into air. The ball falls . [EAMCET (Med.) 1]
  • a)Outside the car
  • b)In the car to the side of the person
  • c)In the car ahead of the person
  • d)Exactly in the hand which threw it up
Q.15
A force of 100 dynes acts on mass of 5 gm for 10 sec. The velocity produced is. [MNR 1987]
  • a) 2 cm/sec
  • b) 200 cm/sec
  • c)20 cm/sec
  • d)2000 cm/sec
Q.16
A light spring balance hangs from the hook of the other light spring balance and a block of mass M kg hangs from the former one. Then the true statement about the scale reading is . [AIEEE 2003]
  • a) Both the scales read M/2 kg each
  • b) The scale of the lower one reads M kg and of the upper one zero
  • c) Both the scales read M kg each
  • d) The reading of the two scales can be anything but the sum of the reading will be M kg
Q.17
A heavy uniform chain lies on a horizontal table-top. If the coefficient of friction between the chain and table surface is 0.25, then the maximum fraction of length of the chain, that can hang over one edge of the table is. [CBSE PMT 1990]
  • a)20%
  • b) 35%
  • c)25%
  • d)15%
Q.18
A body of mass 2 kg is hung on a spring balance mounted vertically in a lift. If the lift descends with an acceleration equal to the acceleration due to gravity ‘g’, the reading on the spring balance will be . [NCERT 1977]
  • a) 2 kg
  • b) (2×g)kg
  • c)(4×g)kg
  • d) Zero
Q.19
Rocket engines lift a rocket from the earth surface because hot gas with high velocity. [AIIMS 1998; JIP]
  • a) Push against the earth
  • b) React against the rocket and push it up
  • c)Push against the air
  • d)Heat up the air which lifts the rocket
Q.20
A second's pendulum is mounted in a rocket. Its period of oscillation decreases when the rocket. [CBSE PMT 1994]
  • a) Comes down with uniform acceleration
  • b) Moves up with a uniform velocity
  • c) Moves round the earth in a geostationary orbit
  • d) Moves up with uniform acceleration
Q.21
A force of 98 N is required to just start moving a body of mass 100 kg over ice. The coefficient of static friction is
  • a)0.6
  • b) 0.2
  • c)0.4
  • d)0.1
Q.22
Two carts of masses 200 kg and 300 kg on horizontal rails are pushed apart. Suppose the coefficient of friction between the carts and the rails are same. If the 200 kg cart travels a distance of 36 m and stops, then the distance travelled by the cart weighing 300 kg is . [CPMT 1989; DPMT]
  • a) 32 m
  • b) 16 m
  • c)24 m
  • d)12 m
Q.23
Newton's first law of motion describes the following . [MP PMT 1996]
  • a)Energy
  • b)Inertia
  • c)Work
  • d)Moment of inertia
Q.24
A rope of length 5m is kept on frictionless surface and a force of 5N is applied to one of its end. Find tension in the rope at 1m from this end. [RPET 2000]
  • a) 1 N
  • b) 4 N
  • c) 3 N
  • d) 5 N
Q.25
Which of the following statements is not true . [CMC Vellore 198]
  • a)The coefficient of friction between two surfaces increases as the surface in contact are made rough
  • b) Rolling friction is greater than sliding friction
  • c)The force of friction acts in a direction opposite to the applied force
  • d)The coefficient of friction between wood and wood is less than 1
Q.26
A force of 5 N acts on a body of weight 9.8 N. What is the acceleration produced in m/sec[NCERT 1990]
  • a)49.00
  • b)1.46
  • c) 5.00
  • d) 0.51
Q.27
A student attempts to pull himself up by tugging on his hair. He will not succeed. [KCET 2005]
  • d)As the force applied is internal to the system.
  • a) As the force exerted is small
  • b) Newton's law of inertia is not applicable to living beings.
  • c)The frictional force while gripping, is small
Q.28
A man is standing on a weighing machine placed in a lift. When stationary his weight is recorded as 40 kg. If the lift is accelerated upwards with an acceleration of 2m/s2, then the weight recorded in the machine will be . [MP PMT 1994]
  • a) 32 kg
  • b) 42 kg
  • c) 40 kg
  • d) 48 kg
Q.29
A horizontal force of 10 N is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is 0.the weight of the block is . [AIEEE 2003]
  • a)2 N
  • b) 50 N
  • c) 20 N
  • d)100 N
Q.30
The maximum static frictional force is
  • a) Equal to twice the area of surface in contact
  • b) Equal to the area of surface in contact
  • c)Independent of the area of surface in contact
  • d)None of the above
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