CBSE Class 11 Work and Energy — practice questions
120 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice CBSE Class 11 Work and Energy in the app →Newton's first law of motion is also known as the law ofA cricket ball of mass 150 g moving at (3i+4j) m/s is hit to -(3i+4j) m/s. The magnitude of momentum change isConservation of linear momentum in a collision follows directly fromA force F acts on a 2 kg body for 3 s, changing its speed from 2 m/s to 8 m/s along the line of F. The magnituThe maximum static friction force on a body is f = μN. Static friction is best described asA 10 kg block on a frictionless surface is pulled by 20 N horizontally and 20 N at 60° above horizontal. The hImpulse equalsA body in equilibrium under several forces hasA 0.5 kg ball hits a wall at 10 m/s and rebounds at 10 m/s. The impulse on the ball isNewton's second law in vector form isA lift accelerates upward at 2 m/s². The apparent weight of a 50 kg person (g=10) isTwo blocks of 2 kg and 3 kg connected by a string are pulled by 10 N on the 3 kg block (frictionless). The accThe SI unit of force, the newton, equalsPer NCERT §4.2, Aristotle's fallacy held that a force is required for which condition?Per NCERT §4.3 (Galileo's double-incline experiment), a ball released on a frictionless incline rises on the oPer NCERT §4.3, INERTIA of a body is best described as which property?Per NCERT §4.4, Newton's FIRST law states which of the following?Per NCERT §4.4, the QUANTITATIVE measure of inertia of a body is which physical quantity?Per NCERT §4.5 (definition of momentum), the momentum p of a body of mass m moving with velocity v is which?Per NCERT §4.5, momentum p is a vector with direction along which vector?Per NCERT §4.5, why is a SHORTER stopping time more painful when catching a cricket ball?Per NCERT §4.4, when a stationary bus suddenly starts, passengers are jerked backward primarily because of whiPer NCERT §4.3 (frictionless horizontal surface), a body moving on it must do which?Per NCERT §4.4 (terrestrial bodies), when an object on Earth is at rest, the gravitational force on it is balaPer NCERT §4.4, the SI unit of momentum is which?Per NCERT §4.5 (Summary 4), Newton's SECOND law in SI units states which relation?Per NCERT §4.5, the SI unit of force is the newton, with one newton equal to which value?Per NCERT §4.5 (Impulse), the IMPULSE J of a force F acting for time Δt equals which quantity?Per NCERT §4.5, an IMPULSIVE FORCE is best described by which feature?Per NCERT Example 4.4, a 0.15 kg cricket ball at 12 m/s is hit back at 12 m/s along the same line. The impulsePer NCERT §4.5, a constant force applied for the SAME time to two bodies of different masses (initially at resPer NCERT §4.5, the dimensions of FORCE are which set?Per NCERT §4.5, the second law F = m a is valid in which kind of reference frame?Per NCERT §4.5, for a body of constant mass, the second law reduces to which form?Per NCERT §4.5, the impulse-momentum theorem states that the impulse on a body equals which quantity?Per NCERT §4.5, the dimensions of IMPULSE are the same as those of which quantity?Per NCERT §4.5, the SI unit of IMPULSE is which?Per NCERT §4.6, Newton's THIRD law states that action and reaction forces are which?Per NCERT §4.6, two forces on the SAME body that happen to be equal and opposite (e.g. gravity vs normal forcePer NCERT §4.6 example, the third-law REACTION to Earth pulling a stone downward (with force mg) is which forcPer NCERT §4.7, the total momentum of an ISOLATED system (no external force) is which?Per NCERT §4.7, conservation of momentum applies in which kind of collisions between two bodies?Per NCERT §4.7, in a recoil scenario (a bullet of mass m fired at v from a rifle of mass M, initially at rest)Per NCERT Example 4.5, when a billiard ball strikes the wall normally at speed u and reflects at speed u, the Per NCERT §4.6, the force of attraction on a stone by Earth and the force of attraction on Earth by the stone Per NCERT §4.6, when you push a wall, the wall pushes back with which force?Per NCERT §4.8 (equilibrium of a particle), the necessary condition for a particle to be in EQUILIBRIUM is whiPer NCERT §4.7 (Summary), the SI unit of force from Newton's second law is which?Per NCERT §4.6 (action and reaction labelling), which statement about the labels is true?Per NCERT §4.9.1, the maximum STATIC friction force on a block on a horizontal surface obeys which inequality?Per NCERT §4.9.1, KINETIC (sliding) friction is approximately given by which relation?Per NCERT §4.9.1, the coefficients of static and kinetic friction satisfy which order?Per NCERT Example 4.7, the MAXIMUM acceleration of a train such that a box on its floor (μ_s = 0.15) remains sPer NCERT Example 4.8 (inclined plane), if a mass just starts to slide at angle θ = 15°, the coefficient of stPer NCERT §4.9.1 (rolling friction note), among rolling, sliding (kinetic), and static friction, which is typiPer NCERT §4.10 eqn 4.16, the CENTRIPETAL force needed for a body of mass m moving at speed v in a circle of rPer NCERT §4.10 eqn 4.18, the maximum speed of a car on a LEVEL circular road of radius R is which?Per NCERT §4.10 eqn 4.22, the OPTIMUM speed (no friction needed) on a banked road of angle θ is which?Per NCERT §4.10 eqn 4.21, the MAXIMUM speed on a banked road (with friction μ_s) is which expression?Per NCERT Example 4.10, a cyclist taking a R=3 m turn at 18 km/h (μ_s = 0.1) is in which condition?Per NCERT Example 4.11, a R=300 m banked-at-15° racetrack with μ = 0.2 has optimum speed approximately which vPer NCERT §5.1.1 (scalar product), A · B equals which expression?Per NCERT §5.1.1, the dot product of two PERPENDICULAR vectors is which value?Per NCERT §5.1.1, î · î (dot product of a unit vector with itself) equals which value?Per NCERT §5.3, the WORK done by a constant force F on an object undergoing displacement d is which?Per NCERT §5.3, work done by a force perpendicular to the displacement (e.g. centripetal force in UCM) is whicPer NCERT §5.3 + Points 2, work done by FRICTION (or viscous force) on a moving body is which?Per NCERT §5.4, the KINETIC energy of a body of mass m moving with speed v is which?Per NCERT §5.2, the WORK-ENERGY theorem states that net work done equals which quantity?Per NCERT §5.4, the kinetic energy is which kind of quantity?Per NCERT Example 5.4, a bullet of mass 50 g at 200 m/s emerges from plywood with 10% of initial KE. The emergPer NCERT §5.4, the dimensions of kinetic energy (and of work) are which?Per NCERT §5.1.1 (Summary 7), the scalar product is which property algebraically?Per NCERT §5.5, the work done by a VARIABLE force F(x) over displacement from x_i to x_f is which?Per NCERT §5.7, the GRAVITATIONAL potential energy of a mass m at height h above the ground (g constant) is whPer NCERT §5.7 / 5.8, a force is CONSERVATIVE if work done over a closed path equals which value?Per NCERT §5.8 eqn 5.9, a conservative force F(x) is related to its potential V(x) by which relation?Per NCERT §5.8, the principle of CONSERVATION OF MECHANICAL ENERGY holds when which condition is satisfied?Per NCERT §5.8 example, a ball dropped from height h has speed at the ground equal to which value?Per NCERT §5.8 (smooth inclined plane), an object released from rest at height h on a frictionless incline reaPer NCERT §5.8 (Points 8), is there an associated POTENTIAL ENERGY for FRICTION?Per NCERT §5.7 (Points 7), the zero of GRAVITATIONAL potential energy is conventionally chosen at which level?Per NCERT §5.7, the dimensions of POTENTIAL energy are the same as those of which quantity?Per NCERT §5.8, an object dropped from height h, just before hitting the ground, has kinetic energy equal to wPer NCERT §5.8 (conservation form), the total mechanical energy E in a conservative system is which sum?Per NCERT §5.9 eqn 5.16, Hooke's law for an ideal spring states the spring force F_s is which?Per NCERT §5.9, the SI unit of the spring constant k is which?Per NCERT §5.9 (Summary 6), the elastic potential energy stored in a spring extended by x is which?Per NCERT §5.9 Fig 5.8, in a spring-mass system at maximum extension (x = ±x_max), the kinetic energy of the bPer NCERT §5.9 Fig 5.8, at the equilibrium position (x = 0) of a spring-mass system, the kinetic energy is whiPer NCERT §5.9 example (5.8), a 1000 kg car at 18.0 km/h (= 5 m/s) hits a spring with k = 5.25×10³ N/m. MaximuPer NCERT §5.10, AVERAGE power is defined as which ratio?Per NCERT §5.10, INSTANTANEOUS power is given by which expression in terms of F and v?Per NCERT §5.10, 1 horsepower (hp) is approximately equal to which value?Per NCERT §5.10, the unit kilowatt-hour (kWh) measures which physical quantity?Per NCERT Example 5.10, a 1800 kg elevator going up at 2 m/s against 4000 N friction needs minimum motor powerPer NCERT §5.10 + Summary, the dimensions of POWER are which?Per NCERT §5.11.1, an ELASTIC collision conserves which two quantities?Per NCERT §5.11.1, in an INELASTIC collision, which quantity is conserved (and which is not)?Per NCERT §5.11.2 eqn 5.22, in a COMPLETELY inelastic 1D collision (mass m₁ at v₁ hits m₂ at rest), the commonPer NCERT §5.11.2, the KINETIC energy LOST in a completely inelastic 1D collision (m₁ at v₁ hitting m₂ at restPer NCERT §5.11.2 eqn 5.26 / 5.27, in an ELASTIC 1D collision of m₁ (v₁) with m₂ (at rest), the final velocityPer NCERT §5.11.2 Case I, in an elastic 1D collision between EQUAL masses (one at rest), the result is which?Per NCERT §5.11.2 Case II, in an elastic 1D collision where a LIGHT mass hits a much HEAVIER stationary mass (Per NCERT Example 5.11, in an elastic collision between a neutron and DEUTERIUM (m₂ = 2 m₁), the fraction of nPer NCERT Example 5.12 (2D elastic between EQUAL masses, one at rest), the two final velocities make which angPer NCERT §5.11.1, two cars colliding and locking together (no rebound) is an example of which collision type?Per NCERT §5.11 (Points 9), during the collision interval itself, conservation of momentum holds at which momePer NCERT §5.11.3 (2D collisions), how many conservation equations does linear momentum yield in 3D?A coin sitting on a bus seat slides forward when the bus brakes suddenly. This is best explained by:A batsman strikes a ball of mass $0.15$ kg moving at $20$ m/s, sending it back at $20$ m/s. The impulse on theA gun of mass $4$ kg fires a bullet of mass $0.04$ kg at $300$ m/s. Recoil speed of the gun is:A book sliding across a smooth wooden desk gradually slows and stops. The force responsible is:A porter carries a $20$ kg bag horizontally for $50$ m at constant height. The work done by him on the bag agaA cricket ball of mass $0.15$ kg moves at $20$ m/s. Its kinetic energy is:A delivery boy raises a $10$ kg sack to a $2$ m shelf in $4$ s. The power expended (using $g = 10$ m/s$^2$) isA carrom coin elastically collides head-on with another identical coin at rest. After collision:The SI unit of work and energy is the:The joule is named after the physicist:James Prescott Joule lived from 1811 until: