one kg mass suspended by a thread is first lifted up with an acceleration g / 2 and then lowered downward with an acceleration g / 2. The ratio of the tensions in the first and second case is

1.1:02

2.2:01

3.1:03

4.3:01

**Posted Date**:-2021-09-27 05:52:02

A 1 kg object suspended by a thread is (i) lifted up with an acceleration of g / 2 (ii) lowered with an acceleration of g / 2. The ratio of the tensions in the two cases is

1.1:02

2.1:03

3.2:01

4.3:01

**Posted Date**:-2021-09-27 05:52:02

A 4 kg block is placed on a rough floor. The coefficient of static friction is 0.8. If a force of 19 N is applied on the block parallel to the floor then the force of friction between the block and floor is

1.32 N

2.18 N

3.19 N

4.9.8 N

**Posted Date**:-2021-09-27 05:52:02

A 40N block is supported by two ropes. One rope is horizontal and the other makes an angle of 30 degree with the ceiling. The tension in the rope attached to the ceiling is approximately:

1.80N

2.40N

3.34.6N

4.32.3

**Posted Date**:-2021-09-27 05:52:02

A ball hangs from a string inside a rail road car moving along a straight track. The string is observed to be inclined towards the rear of the car making a constant small angle with vertical. It shows that the car is

1.moving with a uniform acceleration

2.moving with a uniform velocity

3.moving with a uniform retardation

4.moving with an acceleration which is increasing uniformly.

**Posted Date**:-2021-09-27 05:52:02

A bicycle is in motion. When it is not pedaled the force of friction exerted by the ground on the two wheels is such that it acts:

1.in the backward direction on the front wheel and in the forward direction on the rear wheel

2.in the forward direction on the front wheel and in the backward direction on rear wheel

3.in the backward direction on both the front and the rear wheels

4.in the forward direction on both the front and the rear wheel

**Posted Date**:-2021-09-27 05:52:02

A block A of mass 2 kg rests on another block B of mass 8 kg which rests on a horizontal floor. The coefficient of friction between A and B is 0.2 while that between B and floor is 0.5. When a horizontal force 25 N is applied on the block B the force of friction between A and B is:

1.zero

2.3.9 N

3.5.0 N

4.49 N

**Posted Date**:-2021-09-27 05:52:02

A block has weight W and it is held against a vertical wall by applying a horizontal force F. The minimum value of F is

1.less than W

2.equal to W

3.greater than W

4.not settled by the data

**Posted Date**:-2021-09-27 05:52:02

A block is moving up an inclined plane of inclination 60 degree with velocity of 20 m/s and stops after 2.00 s. If g = 10 m/second square then the approximate value of coefficient of friction is:

1.3

2.3.3

3.0.27

4. 0.33

**Posted Date**:-2021-09-27 05:52:02

A block is released from top of a smooth inclined plane. It reaches the bottom of the plane in 6 s. The time taken by the body to cover the first half of the inclined plane is:

1.3s

2.4s

3.3v2s

4.5s

**Posted Date**:-2021-09-27 05:52:02

A block of mass 0.1 kg is held against a wall by applying a horizontal force of 5N on the block. If the coefficient of friction between the block and the wall is 0.5 the magnitude of the frictional force acting on the block is:

1.25N

2.0.98N

3.4.9N

4.0.49N

**Posted Date**:-2021-09-27 05:52:02

A block of mass 10 kg is suspended through two light springs which are balanced as shown in the figure. Then:

1.both the scales will read 10 kg

2.both the scales will read 5 kg

3.the upper scale will read 10 kg and the lower zero

4.the readings may be of any value but their sum will be 10 kg

**Posted Date**:-2021-09-27 05:52:02

A block of mass 2 kg is placed on the floor. The coefficient of static friction is 0.4. If a force of 2.8 N is applied on the block parallel to floor the force of friction between the block and floor is: (Take g = 10 m/second square)

1.2.8N

2.8N

3.2N

4.none of these

**Posted Date**:-2021-09-27 05:52:02

A block of mass 3 kg is in contact with a block of mass 2 kg. Both the blocks rest on a frictionless floor. A horizontal force of 10 N is applied to push the block of mass 3 kg. The force with which the first block pushes the second block is

1.0 N

2.4 N

3.6 N

4.10 N

**Posted Date**:-2021-09-27 05:52:02

A block of mass 4 kg is kept on a rough horizontal surface. The coefficient of static friction is 0.8. If a force of 19 N is applied on the block parallel to the floor then the force of friction between the block and floor is:

1.32N

2.18N

3.19N

4.9.8N

**Posted Date**:-2021-09-27 05:52:02

A block of mass 4 kg rests on an inclined plane. The inclination of the plane is gradually increased. It is found that when the inclination is 3 in 5 the block just begin to slide down the plane. The coefficient of friction between the block and the plane is

1.0.4

2.0.6

3.0.8

4.0.75

**Posted Date**:-2021-09-27 05:52:02

A block of mass M is pulled along a horizontal frictionless surface by a rope of mass m. Force P is applied at one end of the rope. The force which the rope exerts on the block is

1.P / M(m + M)

2.P / M - m

3.Pm / M - m

4.PM / m + M

**Posted Date**:-2021-09-27 05:52:02

A block of mass M is suspended by a string A from the ceiling and another string B is connected to the bottom of the block. If B is pulled on steadily:

1.A breaks earlier than B

2.B breaks earlier than A

3.both break simultaneously not possible to say which

4.one will break earlier

**Posted Date**:-2021-09-27 05:52:02

A block of mass M is suspended from the ceiling of a room through a metal chain of mass m. The ceiling pulls the chain upwards with forces

1.mg

2.mc

3.(m + M)g

4.zero

**Posted Date**:-2021-09-27 05:52:02

A block rests on a rough inclined plane making an angle of 30 degree with the horizontal. The coefficient of static friction between he block and the plane is 0.8. If the frictional force on the block is 10N the mass of the block in (kg) is: (Take g = 10 m/second square)

1.2

2.4

3.1.6

4.2.5

**Posted Date**:-2021-09-27 05:52:02

A body is at rest on the surface of the earth. Which of the following statements is correct?

1.No force is acting on the body

2.Only weight of the body acts on it

3.Net downward force is equal to the net upward force

4.None of the above statement is correct

**Posted Date**:-2021-09-27 05:52:02

A body of mass 10 kg is to be raised by a massless string from rest to rest through a height 9.8 m. The greatest tension which the string can safely bear is 20 kg wt. The least time of ascent is:

1.2 s

2.3 s

3.4 s

4.none of these

**Posted Date**:-2021-09-27 05:52:02

A body of mass 32 kg is suspended by a spring balance from the roof of a vertically operating lift and going downward from rest. At the instant the lift has covered 20 m and 50 m the spring balance showed 30 kg and 36 kg respectively. Then the velocity of the lift is

1.increasing at 20 m and increasing at 50 m

2.increasing at 20 m and decreasing at 50 m

3.continuously decreasing at a steady rate throughout the journey.

4.constantly increasing at constant rate throughout the journey.

**Posted Date**:-2021-09-27 05:52:02

A body weighs 8 g when placed in one pan and 18 g when placed on the other pan of a false balance. If the beam is horizontal when both the pans are empty the true weight of the body is:

1.13 g

2.12 g

3.15.5 g

4.15 g

**Posted Date**:-2021-09-27 05:52:02

A box weighing 20 N is moved along a horizontal surface through a distance of 25 m. If the coefficient of friction is 0.4 the work done against friction is

1.200 J

2.250 J

3.500 J

4.100 J

**Posted Date**:-2021-09-27 05:52:02

A chain lies on a rough horizontal table. It starts sliding when one-fourth of its length hangs over the edge of the table. The coefficient of static friction between the chain and the surface of the table is:

1.2-Jan

2.3-Jan

3.4-Jan

4.5-Jan

**Posted Date**:-2021-09-27 05:52:02

A disc of mass 100 g is kept floating horizontally in air by firing bullets each of mass 5 g with the same velocity at the same rate of 10 bullets/s. The bullets rebound with the same speed in opposite direction the velocity of each bullet at the time of impact is:

1.196 cm/s

2.9.8 cm/s

3.98 cm/s

4.980 cm/s

**Posted Date**:-2021-09-27 05:52:02

A heavy uniform chain lies on a horizontal table top. If the coefficient of friction between the chain and the table is 0.25 then the maximum percentage of the length of the chain that can hang over one edge of the table is

1.20%

2.25%

3.35%

4.15%

**Posted Date**:-2021-09-27 05:52:02

A heavy uniform chain lies on a horizontal top of table. If the coefficient of friction between the chain and the table is 0.25 then the maximum percentage of the length of the chain that can hang over one edge of the table is:

1.20%

2.25%

3.35%

4.15%

**Posted Date**:-2021-09-27 05:52:02

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 0.2. The weight of the block is:

1.20N

2.50N

3.100N

4.2N

**Posted Date**:-2021-09-27 05:52:02

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:

1.both the scales read M kg each

2.the scale of the lower one reads M kg and of the upper one zero

3.the reading of the two scales can be anything but the sum of the reading will be M kg

4.both the scales read M/2 kg

**Posted Date**:-2021-09-27 05:52:02

A machine gun fires 10 bullets/s each of mass 10g the speed of each bullet is 20 cm/s then force of recoil is:

1.200 dyne

2.2000 dyne

3.20 dyne

4.none of these

**Posted Date**:-2021-09-27 05:52:02

A man is pulling a rope attached to a block on a smooth horizontal table. The tension in the rope will be the same at all points:

1.if and only if the rope is not accelerated

2.if and only if the rope is massless

3.if either the rope is not accelerated or is massless

4.always

**Posted Date**:-2021-09-27 05:52:02

A marble block of mass 2 kg lying on ice when given a velocity of 6 m/s is stopped by friction in 10s. Then the coefficient of friction is:

1.0.02

2.0.03

3.0.06

4.0.01

**Posted Date**:-2021-09-27 05:52:02

A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle. The motion of the particle takes place in a plane. It follows that:

1.its velocity is constant

2.its kinetic energy is constant

3.it moves in a circular path

4.both B and C are correct

**Posted Date**:-2021-09-27 05:52:02

A partly hanging uniform chain of length L is resting on a rough horizontal table. l is the maximum possible length that can hang in equilibrium. The coefficient of friction between the chain and table is

1.l / L - l

2.L / l

3.l / L

4.l L / L + l

**Posted Date**:-2021-09-27 05:52:02

A rope of length L is pulled by a constant force F. What is the tension in the rope at a distance x from the end where the force is applied ?

1.FL / x

2.F (L - x) / L

3.FL / L - x

4.Fx / L - x

**Posted Date**:-2021-09-27 05:52:02

A simple pendulum hangs from the roof of a moving train. The string is inclined towards the rear of the train. What is the nature of motion of the train?

1.Accelerated

2.Uniform

3.Retarded

4.None of these

**Posted Date**:-2021-09-27 05:52:02

A simple pendulum hangs from the roof of a moving train. The string is inclined towards the rear of the train. What is the nature of motion of the train?

1.Accelerated

2.Uniform

3.Retarded

4. None of these

**Posted Date**:-2021-09-27 05:52:02

A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring reads 49 N when the lift is stationary. If the lift moves downward with an acceleration of 5 m/square second the reading of the spring balance will be:

1.24N

2.74N

3.15N

4.49N

**Posted Date**:-2021-09-27 05:52:02

A stone is accelerated upwards by a cord whose breaking strength is three times the weight of the stone. The maximum acceleration with which the stone can be moved up without breaking the cord is

1.g

2.2g

3.3g

4.zero

**Posted Date**:-2021-09-27 05:52:02

A system is accelerated upward with an acceleration 5 g. The apparent weight of a body of mass m in the system is

1.mg N

2.5mg N

3.6mg N

4.8mg N

**Posted Date**:-2021-09-27 05:52:02

A uniform chain is coiled up on a horizontal plane and one end passes over a small light pulley at a height a above the plane. Initially a length b hangs freely on the other side. If b = 2a:

1.the end descends with a constant acceleration g/3

2.the end descends with acceleration depends upon hanging position

3.acceleration can not be determined

4.acceleration is variable

**Posted Date**:-2021-09-27 05:52:02

A uniform chain is coiled up on a horizontal plane and one end passes over a small light pulley at a height a above the plane. Initially a length b hangs freely on the other side. If b = 2a:

1.the end descends with a constant acceleration g/3

2.the end descends with acceleration depends upon hanging position

3.acceleration can not be determined

4.acceleration is variable

**Posted Date**:-2021-09-27 05:52:02

A weight w is suspended from the midpoint of a rope whose ends are at the same level. In order to make the rope perfectly horizontal the force applied to each of its ends must be:

1.less than w

2.equal to w

3.equal to 2w

4.infinitely large

**Posted Date**:-2021-09-27 05:52:02

An elevator and its load have a total mass of 800 kg. The elevator is originally moving downwards at 10 m/s it slows down to stop with constant acceleration in a distance of 25 m. Find the tension T in the supporting cable while the elevator is being brought to rest. (Take g = 10 m/square second)

1.8000N

2.1600N

3.9600N

4.6400N

**Posted Date**:-2021-09-27 05:52:02

An empty plastic box of mass 5 kg is observed to accelerate up at the rate of g / 6 when placed deep inside water. What mass of sand should be put inside the box so that it may accelerate down at the rate of g / 6?

1.1 kg

2.1.5 kg

3.2 kg

4.2.5 kg

**Posted Date**:-2021-09-27 05:52:02

An isolated particle of mass m is moving in a horizontal plane (XY plane) along x-axis at a certain height above the ground. It suddenly explodes into two fragments of masses m / 4 and 3m / 4. An instant later the smaller fragment is at y = + 15 cm. The larger fragment at this instant is at y =

1.- 5 cm

2.+ 5 cm

3.+ 20 cm

4.- 20 cm

**Posted Date**:-2021-09-27 05:52:02

An open knife edge of mass 200 g is dropped from height 5 m on a cardboard. If the knife edge penetrates distance 2 m into the cardboard the average resistance offered by the cardboard to the knife edge is:

1.7N

2.25N

3.35N

4.none of these

**Posted Date**:-2021-09-27 05:52:02

An open knife edge of mass M is dropped from a height h on a wooden floor. If the blade penetrates distance S into the wood the average resistance offered by the wood to the blade is

1.Mg

2.Mg (1 - h / S)

3.Mg (1 = h / S)

4.Mgh

**Posted Date**:-2021-09-27 05:52:02

Brakes of a very small contact area are not used although friction is independent of area. It is because friction:

1.depends on the nature of the material

2.cause wear and tear

3.resists motion

4.operating in this case is sliding friction

**Posted Date**:-2021-09-27 05:52:02

Choose the correct option or options.

1.Tension force always pulls a body

2.Tension can never push a body or rope

3.Tension across massless or frictionless pulley remains constant

4.Rope becomes slack when tension force becomes zero

**Posted Date**:-2021-09-27 05:52:02

e normal reaction on a body placed in a lift moving up with constant acceleration 2 m/square second is 120N. Mass of body is: (Take g = 10 m/square second)

1.10 kg

2.15 kg

3.12 kg

4.None of these

**Posted Date**:-2021-09-27 05:52:02

For the equilibrium of a body on an inclined plane of inclination 450 the coefficient of static friction will be:

1.greater than one

2.less than one

3.zero

4.less than zero

**Posted Date**:-2021-09-27 05:52:02

he coefficient of kinetic friction between a 20 kg box and the floor is 0.40. How much work does a pulling force do on the box is pulling it 8.0 m across the floor at constant speed? The pulling force is directed 37 degree above the horizontal:

1.343J

2.482J

3.14.4J

4.None of these

**Posted Date**:-2021-09-27 05:52:02

In the superhit film Raja Hindustani Amir Khan greets his beloved by shaking hand. What kind of force do they exert?

1.Nuclear

2.Gravitational

3.Weak

4.Electromagnetic

**Posted Date**:-2021-09-27 05:52:02

In which of the following cases the net force is not zero?

1.A kite skillfully held stationary in the sky

2.A ball freely falling from a height

3.An aeroplane rising upwards at an angle of 45 degree with the horizontal with a constant speed

4.A cork floating on the surface of water

**Posted Date**:-2021-09-27 05:52:02

Mark correct option or options.

1.Friction always opposes the motion of a body

2.Friction only opposes the relative motion between surfaces

3.Kinetic friction depends on the speed of body when the speed of body is less than 10 m/s

4.The coefficient of friction is always less than or equal to one

**Posted Date**:-2021-09-27 05:52:02

Mark correct option or options.

1.The body of greater mass needs more forces to move due to more inertia

2.Force versus time graph gives impulse

3.Microscopic area of contact is about 10-4 times actual area of the contact

4.All of the above

**Posted Date**:-2021-09-27 05:52:02

n small balls each of mass m impinge elastically each second on a surface with velocity u. The force experienced by the surface will be

1.mnu

2.2 mnu

3.4 mnu

4.1 / 2 mnu

**Posted Date**:-2021-09-27 05:52:02

Starting from rest a body slides down a 45 degree inclined plane in twice the time it takes to slide down the same distance in the absence of friction. The coefficient of friction between the body and the inclined plane is:

1.0.33

2.0.25

3.0.75

4.0.8

**Posted Date**:-2021-09-27 05:52:02

teady rain giving 5 m m an hour turns suddenly into a downpour giving 20 mm an hour and the speed of the rain drops falling vertically on to a flat foof simultaneously doubles. The pressure exerted by the falling rain on the roof is raised by a factor of

1.4

2.8

3.16

4.32

**Posted Date**:-2021-09-27 05:52:02

The action and reaction forces referred to newtons third law of motion:

1.must act upon the same body

2.must act upon different bodies

3.need not to be equal in magnitude but must have the same line of action must be equal in

4.magnitude but need not have the same line of action

**Posted Date**:-2021-09-27 05:52:02

The action and reaction forces referred to newtons third law of motion:

1.must act upon the same body

2.must act upon different bodies

3.need not to be equal in magnitude but must have the same line of action

4.must be equal in magnitude but need not have the same line of action

**Posted Date**:-2021-09-27 05:52:02

The coefficient of kinetic friction between a 20 kg box and the floor is 0.40. How much work does a pulling force do on the box is pulling it 8.0 m across the floor at constant speed? The pulling force is directed 37 degree above the horizontal:

1.343J

2.482J

3.14.4J

4.None of these

**Posted Date**:-2021-09-27 05:52:02

The minimum velocity (in m/s) with which a car driver must traverse a flat curve of radius 150 m and coefficient of friction 0.6 to avoid skidding is:

1.60 m/s

2.30 m/s

3.15 m/s

4.25 m/s

**Posted Date**:-2021-09-27 05:52:02

The normal reaction on a body placed in a lift moving up with constant acceleration 2 m/square second is 120N. Mass of body is: (Take g = 10 m/square second)

1.10 kg

2.15 kg

3.12 kg

4.5 kg

**Posted Date**:-2021-09-27 05:52:02

The ratio of the weight of a man in a stationary lift and in a lift accelerating downwards with a uniform acceleration a is 3 : 2. The acceleration of the lift is

1.g / 3

2.g / 2

3.g

4.2g

**Posted Date**:-2021-09-27 05:52:02

The ratio of the weight of a man in a stationary lift and when it is moving downwards with uniform acceleration a is 3:2 then the value of a is:

1.3/2 g

2.g/3

3.g

4.2/3 g

**Posted Date**:-2021-09-27 05:52:02

Two bodies have same mass and speed then:

1.their momentums are same

2.the ratio of momentums is not determined

3.the ratio of their magnitudes of momentum is one

4.both B and C are correct

**Posted Date**:-2021-09-27 05:52:02

Two bodies of masses 6 kg are tied to the ends of a string which passes over a fixed pulley of the Atwoods machine. The total downward thrust on the pulley is nearly

1.59.8 N

2.69.8 N

3.7 9.8 N

4.8 9.8 N

**Posted Date**:-2021-09-27 05:52:02

Two masses 5 kg and 3 kg are suspended from the ends of an inextensible light string passing over a frictionless pulley. When the masses are released the force exerted by the string on the pulley is

1.5g

2.8g

3.7.5g

4.15g

**Posted Date**:-2021-09-27 05:52:02

Water jet issues water from a nozzle of 2 square cm cross-section with velocity 30 cm/s and strikes a plane surface placed at right angles to the jet. The force exerted on the plane is:

1.200 dyne

2.400 dyne

3.1800 dyne

4.none of these

**Posted Date**:-2021-09-27 05:52:02

When we kick a stone we get hurt. Due to which one of the following properties of the stone it happens?

1.Inertia

2.Velocity

3.Reaction

4.Momentum

**Posted Date**:-2021-09-27 05:52:02

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