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Compare the RMS speed of hydrogen, oxygen, and carbon dioxide at the same temperature.

a. VH2 < VO2 < VCO2 b. VH2 > VO2 > VCO2 c. VH2 > VO2 < VCO2 d. VH2 < VO2 > VCO2 Solution: Answer: (b)As we know that... View Article

A body of mass 1.0 kg is falling with an acceleration of 10 m/s². Its apparent weight will be (g = 10 m/s²)

1) 1.0 kg 2) 2.0 kg 3) 0.5 kg 4) Zero Answer:4) Zero Solution: F = m(g-a) = m(10-10) = 0 ... View Article

A force of 5 N acts on a body of weight 9.8 N. What is the acceleration produced in m/s²?

1) 49.00 2) 5.00 3) 1.46 4) 0.51 Answer: 2) 5.00 Solution: Given, Force, F = 5 N Weight, W = 9.8 N W = mg 9.8 = m x 9.8 m = 1 Kg... View Article

A man getting down a running bus falls forward because

1) Due to inertia of rest, road is left behind and man reaches forward 2) Due to inertia of motion upper part of the body continues to be in... View Article

When a train stops suddenly, passengers in the running train feel an instant jerk in the forward direction because

1) The back of seat suddenly pushes the passengers forward 2) Inertia of rest stops the train and takes the body forward 3) Upper part of the... View Article

A boy presses a book against the front wall such that the book does not move. The force of friction between the wall and the book is

1) Towards right 2) Towards left 3) Downwards 4) Upwards Answer: 4) Upwards Solution: The tendency of the book is to fall due to... View Article

A body is imparted motion from rest to move in a straight line. If it is then obstructed by an opposite force, then

1) The body may necessarily change direction 2) The body is sure to slow down 3) The body will necessarily continue to move in the same... View Article

Statement I: A cloth covers a table. Some dishes are kept on it. The cloth can be pulled out without dislodging the dishes from the table. Statement II: For every action, there is an equal and opposite reaction.

1) Statement I is correct, Statement II is correct, Statement II is a correct explanation for Statement I 2) Statement 1 is correct, Statement... View Article

A player caught a cricket ball of mass 150 g moving at the rate of 20 m/s. If the catching process be completed in 0.1 s the force of the blow exerted by the ball on the hands of the player is

1) 0.3 N 2) 30 N 3) 300 N 4) 3000 N Answer: 2) 30 N Solution: The final velocity of the ball will be zero after catching The... View Article

A particle moves in the XY Plane under the action of a force F such that the components of its linear momentum P at any time t are Px = 2 cost, Py = 2 sint. The angle between F and P at time t is

1) 90o 2) 0o 3) 180o 4) 30o Answer: 1) 90o Solution: From Newtons second law, Force = rate of change of momentum. Hence, F = dP/dt... View Article

10,000 small balls, each weighing 1 g strike one square cm of area per second with a velocity of 100 ms^–1in a normal direction and rebound with the same velocity. The value of pressure on the surface will be

1) 2 x 103 Nm-2 2) 2 x 105 Nm-2 3) 107 Nm-2 4) 2 x 107 Nm-2 Answer: 4) 2 x 107 Nm-2 Solution: No of balls = 10000... View Article

The formula for true force is

1) F = ma 2) F = d(mv)/dt 3) F = m (dv/dt) 4) F = m (d2x/dt2) Answer: 2) F = d(mv)/dt Solution: According to Newton's second law... View Article

The velocity of a body of mass 20 kg decreases from 20ms^–1 to 5ms^–1 in a distance of 100 m. Force on the body is

1) –27.5 N 2) –47.5 N 3) –37.5 N 4) –67.5 N Answer: 3) –37.5 N Solution: The equation of motion is given as v2 = u2 + 2as (5)2 = (20)2 +... View Article

A block of mass M is pulled along a horizontal frictionless surface by a rope of mass m. If a force P is applied at the free end of the rope, the force exerted by the rope on the block is

1) Pm/M+m 2) Pm/M-m 3) P 4) PM/M+m Answer: 4) PM/M+m Solution: Force,P = (M + m)a ⇒ a = P/(M + m) Force exerted by the rope on the... View Article

A block kept on a rough surface starts sliding when the inclination of the surface is θ with respect to the horizontal. The coefficient of static friction between the block and the surface is

1) sec θ 2) sin θ 3) tan θ 4) cos θ Answer: 3) tan θ Solution: Force parallel to the plane, F =... View Article

The force required to move a body up a rough inclined plane is double the force required to prevent the body from sliding down the plane. The coefficient of friction, when the angle of inclination of the plane is 60° is

1) 1/3 2) 1/√2 3) 1/√3 4) 1/2 Answer: 3) 1/√3 Solution: Given, The force required to move a body up a rough... View Article

To determine the coefficient of friction between a rough surface and a block, the surface is kept inclined at 45° and the block is released from rest. The block takes a time t in moving a distance d. The rough surface is then replaced by a smooth surface and the same experiment is repeated. The block now takes a time t/2 in moving down the same distance d. The coefficient of friction is

1) 3/4 2) 5/4 3) 1/2 4) 1/√3 Answer: 1) 3/4 Solution: μ = [1- 1/n2] tanθ ⇒ μ = [1- 1/22] tan450 μ =... View Article

A box is lying on an inclined plane what is the coefficient of static friction if the box starts sliding when an angle of inclination is 60°

1) 1.173 2) 1.732 3) 2.732 4) 1.677 Answer: 2) 1.732 Solution: Tangential component of force = mgsin600 Normal component of force =... View Article

A car travelling at a speed of 30 km/h is brought to a halt in 8 metres by applying brakes. If the same car is travelling at 60 km/h it can be brought to a halt with the same braking power in

1) 8 m 2) 16 m 3) 24 m 4) 32 m Answer:4) 32 m Solution: Fs = (½)mv2 S ∝ v2 On doubling the speed the required distance... View Article

A 0.5 kg ball moving with a speed of 12 ms^–1 strikes a hard wall at an angle of 30^o with the wall. It is reflected with the same speed and at the same angle. If the ball is in contact with the wall for 0.025 s the average force acting on the wall is

1) 96 N 2) 48 N 3) 24 N 4) 12 N Answer: 3) 24 N Solution: F x t = change in momentum = 2mvsinθ F = 2mvsinθ/t... View Article