Work, Energy & Power — Previous-Year Questions

Q1. A 5 N force pulls a box at 30° to the horizontal over 4 m. Work done by the force:

Q2. Force perpendicular to displacement does work equal to:

Q3. A 2 kg block lifted 5 m. Work done against gravity:

Q4. If 50 N moves a body in the OPPOSITE direction over 3 m, work done is:

Q5. 1 joule equals:

Q1. A 2 kg object accelerates from 3 m/s to 7 m/s. Net work done:

Q2. A 0.5 kg ball decelerates from 10 m/s to rest. Work done by friction:

Q3. Work-energy theorem holds when:

Q4. Body of mass 3 kg moves from x = 0 to x = 5 m under F = 4x N. Final velocity (starts at rest):

Q5. Power is the rate of:

Q1. A 4 kg object moves at 5 m/s. Its KE:

Q2. If speed of a body is tripled, KE becomes:

Q3. Two bodies have same KE; their momenta are p₁ and p₂. If their masses are m and 4m:

Q4. A 1 kg body has 50 J KE. Its speed:

Q5. Rolling KE of a sphere of mass M and speed v (about its center I = 2MR²/5):

Q1. Gravitational PE of 1 kg at Earth's surface (M = 6×10²⁴ kg, R = 6.4×10⁶ m):

Q2. An object falls from height h above Earth's surface. Loss in PE (h ≪ R):

Q3. Total energy of a body in circular orbit at radius r:

Q4. Work done by gravity from r₁ to r₂ (r₂ > r₁):

Q5. Gravitational PE near Earth's surface (mgh) is an approximation valid when:

Q1. Energy stored in a spring (k = 100 N/m) stretched by 0.2 m:

Q2. A 0.5 kg mass attached to a spring (k = 50 N/m) is released from rest at x = 0.1 m. Max speed:

Q3. If a spring is stretched by 2x instead of x, energy stored becomes:

Q4. Two springs of k = 100 N/m each are connected in parallel and stretched 0.1 m. Energy stored:

Q5. Force-displacement (F vs x) graph for a spring is:

Q1. A 1 kg ball is dropped from 10 m height. Speed just before hitting ground (g = 10):

Q2. A pendulum bob of mass m starts at height h. Max speed (at lowest point):

Q3. When mechanical energy is NOT conserved:

Q4. A block slides down a frictionless inclined plane from height 5 m. Speed at bottom:

Q5. Energy is conserved in:

Q1. A 60 W bulb on for 1 hour consumes:

Q2. A car of mass 1000 kg accelerates from rest to 20 m/s in 10 s. Avg power:

Q3. A pump lifts 100 kg water/sec to a height of 10 m. Min power:

Q4. Power expression F·v gives instantaneous power because:

Q5. 1 horsepower equals:

Q1. Work done by a spring (k = 200 N/m) as it stretches 0.1 m:

Q2. F = 5x N. Work done from x = 0 to x = 2 m:

Q3. On an F-x graph, area under curve from x₁ to x₂ represents:

Q4. Work done by gravity moving a 1 kg object from r = 2R to r = R (Earth's surface):

Q5. For a conservative force, work done in moving a body from A to B:

Q1. Two equal masses, one at rest. After head-on elastic collision:

Q2. A 2 kg ball at 10 m/s hits a stationary 1 kg ball elastically. Velocities after:

Q3. Elastic collision conserves:

Q4. Heavy mass hitting a stationary light mass elastically:

Q5. Newton's cradle (5 balls, one swung) demonstrates:

Q1. A 2 kg ball at 4 m/s hits a stationary 3 kg ball and they STICK. Final velocity:

Q2. KE lost in the above collision:

Q3. Perfectly inelastic collision:

Q4. Ballistic pendulum: bullet of mass m hits block (M) at speed v and embeds. Block rises h. Bullet speed:

Q5. In ANY collision, what is always conserved?

Q1. A ball dropped from 4 m bounces to 1 m. Coefficient of restitution e:

Q2. If e = 1, the collision is:

Q3. A ball with e = 0.8 falls from 5 m. Height after 2nd bounce:

Q4. Coefficient of restitution depends on:

Q5. Perfectly inelastic collision corresponds to:

Q1. A spring of constant k = 200 N/m is compressed by 0.1 m. The PE stored is:

Q2. A body of mass 2 kg has KE = 16 J. Its speed is:

Q3. In SHM, when displacement is half the amplitude, the fraction of total energy that is kinetic:

Q4. A 0.5 kg block on a spring (k = 50 N/m) oscillates. The time period is:

Q5. A force F = 5x (in N) acts on a body. Work done moving from x=0 to x=2 m: