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10000 small balls, each weighing lg, strike one square centimetre of area per second with a velocity 100 ms^-1 in a normal direction and rebound with the same velocity. The value of pressure on the surface will be

1) 2 × 103 Nm-2 2) 2 × 105 Nm-2 3) 107 Nm-2 4) 2 × 107 Nm-2 Answer: 4) 2... View Article

Two masses of M and 4M are moving with equal kinetic energy. The ratio of their linear momenta is

1) 1 : 8 2) 1 : 4 3) 1 : 2 4) 4 : 1 Answer: 3) 1 : 2... View Article

A bullet of mass 10 g moving with 300 m/s hits a block of ice of mass 5 kg and drops dead. The velocity of ice is

1) 50 cm/s 2) 60 cm/s 3) 40 cm/s 4) 200 cm/s Answer: 2) 60 cm/s Solution: Applying law of conservation... View Article

A rocket of mass 100 kg burns 0.1 kg of fuel per second. If velocity of exhaust gas is 1 kms^-1 , then it lifts with an acceleration of

1) 1000 ms-2 2) 100 ms-2 3) 10 ms-2 4) 1 ms-2 Answer: 4) 1 ms-2 Solution: Mass (m) = 100... View Article

A hockey player receives a corner shot at a speed of 15 ms^-1 at an angle of 30° with the y – axis and then shoots the ball of mass 100 g along the negative x-axis with a speed of 30 ms^-1. If it remains in contact with the hockey stick for 0.01s, the force imparted to the ball in the x-direction is

1) 281.25 N 2) 187.5 N 3) 562.5 N 4) 375 N Answer: Mass of the ball, m = 100... View Article

A shell of mass 10 kg is moving with a velocity of 10 ms^-1 when it blasts and forms two parts of mass 9 kg and 1 kg respectively. If the 1st mass is stationary, the velocity of the 2nd is

1) 1 ms-1 2) 10 ms-1 3) 100 ms-1 4) 1000 ms-1 Answer:3) 100 ms-1 Solution: From the conservation of... View Article

A cricket ball of mass 0.25 kg with a speed of 10 m/s collides with a bat and returns with the same speed within 0.01s. The force acted on the bat is

1) 25 N 2) 50 N 3) 250 N 4) 500 N Answer: 4) 500 N Solution: Δp = 2mv =... View Article

A stationary bomb explodes into three pieces. One piece of 2 kg mass moves with a velocity of 8ms^-1 at right angles to the other piece of mass 1 kg moving with a velocity of 12 ms^-1. If the mass of the third piece is 0.5 kg, then its velocity is

1) 10 ms-1 2) 20 ms-1 3) 30 ms-1 4) 40 ms-1 5) 50 ms-1 Answer: 4) 40 ms-1 Solution: Initial... View Article

A shell of mass 200 g is fired by a gun of mass 100 kg. If the muzzle speed of the shell is 80 m/s, calculate the recoil speed of the gun

1) 16 cm/s 2) 8 m/s 3) 4 m/s 4) 16 m/s Answer: 1) 16 cm/s Solution: Given Mass of the... View Article

A lift is moving down with acceleration a. A man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift and a man standing stationary on the ground are respectively

1) g, g 2) g – a, g – a 3) g – a, g 4) a, g Answer: 3) g... View Article

A force of 1200 N acts on a 0.5 kg steel ball as a result of a collision lasting 25 ms. If the force is in a direction opposite to the initial velocity of 14 ms^-1, then the final speed of the steel ball would be

1) 24 ms-1 2) 35 ms-1 3) 12 ms-1 4) 46 ms-1 Answer: 4) 46 ms-1 Solution: For an impulsive force... View Article

An 80 kg person is parachuting and is experiencing a downward acceleration of 2.8 ms^-2. The mass of the parachute is 5 kg. The upward force on the open parachute is (take, g = 9.8 ms^-2)

1) 595 N 2) 675 N 3) 456 N 4) 925 N Answer: 1) 595 N Solution: m = (80 kg... View Article

Which of the following quantities measured from different inertial reference frames are the same?

1) Force 2) Velocity 3) Displacement 4) Kinetic energy Answer: 1) Force and 4) Kinetic energy Solution: Force and kinetic energy will... View Article

A student unable to answer a question on Newton’s laws of motion attempts to pull himself up by tugging on his hair. He will not succeed

1) as the force exerted is small 2) the frictional force while gripping, is small 3) Newton’s law of inertia... View Article

A man slides down on a telegraphic pole with an acceleration equal to one-fourth of acceleration due to gravity. The frictional force between man and pole is equal to in terms of man’s weight w

1) W/4 2) W/2 3) 3W/4 4) W Answer: 3) 3W/4 Solution: Given a = g/4 ma = W – f... View Article

Earth comes between sun and moon during a (A) solar eclipse (B) lunar eclipse (C) annular eclipse (D) total solar eclipse

lunar eclipse Also known as the eclipse of the moon, it occurs when the earth comes in between the sun... View Article

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