If we throw a body upwards with velocity of 4 m/s, at what height does its kinetic energy reduce to half of the initial value? (Take g = 10 m s-2)
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Solution
300 J of work is done in sliding a 2 kg block up an inclined plane of height 10 m. Taking g = 10 m/s2 work done against friction is
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Solution
Total work done in sliding = work done against gravity+ work done against friction
or, 300J = mgh +work done against friction
⇒ Work done against friction
= 300J – 2 × 10 × 10J = 100 J
A ball of mass 4 kg moving with velocity 3m/s, collides with spring of natural length 2 m and force constant 144 N/m. What will be the length of compressed spring?
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A bullet of mass 20 g and moving with 600 m/s collides with a block of mass 4 kg hanging with the string. What is the velocity of bullet when it comes out of block, if block rises to height 0.2 m after collision?
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Solution
A train of weight 107 N is running on a level track with uniform speed of 36 km h-1. The frictional force is 0.5 kg per quintal. If g = 10 m/s2, then power of engine is
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If the mass of the body is halved and velocity gets doubled then final kinetic energy would be ………of initial
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If the kinetic energy of a body is increased by 300%, the momentum of the body is increased by
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Solution
An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 ms–1 and the second part of mass 2 kg moves with speed 8 ms–1. If the third part flies off with speed 4 ms–1 then its mass is
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Solution
A uniform force of \((3\hat{i}+\hat{j})\) newton acts on a particle of mass 2 kg. The particle is displaced from position \((2\hat{i}+\hat{k})\) meter to position \((4\hat{i}+3\hat{j}-\hat{k})\) meter. The work done by the force on the particle is
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