CBSE Class 11 (Science) Work, Energy and Power — practice questions
117 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice CBSE Class 11 (Science) Work, Energy and Power in the app →As per your syllabus, A · B equals which expression?As per your syllabus, the dot product of two PERPENDICULAR vectors is which value?As per your syllabus, î · î (dot product of a unit vector with itself) equals which value?As per your syllabus, the WORK done by a constant force F on an object undergoing displacement d is which?As per your syllabus, work done by a force perpendicular to the displacement (e.g. centripetal force in UCM) iAs per your syllabus, + Points 2, work done by FRICTION (or viscous force) on a moving body is which?As per your syllabus, the KINETIC energy of a body of mass m moving with speed v is which?As per your syllabus, the WORK-ENERGY theorem states that net work done equals which quantity?As per your syllabus, the kinetic energy is which kind of quantity?As per your syllabus, a bullet of mass 50 g at 200 m/s emerges from plywood with 10% of initial KE. The emergeAs per your syllabus, the dimensions of kinetic energy (and of work) are which?As per your syllabus, the scalar product is which property algebraically?As per your syllabus, the work done by a VARIABLE force F(x) over displacement from x_i to x_f is which?As per your syllabus, the GRAVITATIONAL potential energy of a mass m at height h above the ground (g constant)As per your syllabus, / 5.8, a force is CONSERVATIVE if work done over a closed path equals which value?As per your syllabus, eqn 5.9, a conservative force F(x) is related to its potential V(x) by which relation?As per your syllabus, example, a ball dropped from height h has speed at the ground equal to which value?As per your syllabus, is there an associated POTENTIAL ENERGY for FRICTION?As per your syllabus, the zero of GRAVITATIONAL potential energy is conventionally chosen at which level?As per your syllabus, the dimensions of POTENTIAL energy are the same as those of which quantity?As per your syllabus, an object dropped from height h, just before hitting the ground, has kinetic energy equaAs per your syllabus, the total mechanical energy E in a conservative system is which sum?As per your syllabus, eqn 5.16, Hooke's law for an ideal spring states the spring force F_s is which?As per your syllabus, the SI unit of the spring constant k is which?As per your syllabus, the elastic potential energy stored in a spring extended by x is which?As per your syllabus, Fig 5.8, in a spring-mass system at maximum extension (x = ±x_max), the kinetic energy oAs per your syllabus, Fig 5.8, at the equilibrium position (x = 0) of a spring-mass system, the kinetic energyAs per your syllabus, AVERAGE power is defined as which ratio?As per your syllabus, INSTANTANEOUS power is given by which expression in terms of F and v?As per your syllabus, 1 horsepower (hp) is approximately equal to which value?As per your syllabus, the unit kilowatt-hour (kWh) measures which physical quantity?As per your syllabus, a 1800 kg elevator going up at 2 m/s against 4000 N friction needs minimum motor power aAs per your syllabus, + Summary, the dimensions of POWER are which?As per your syllabus, an ELASTIC collision conserves which two quantities?As per your syllabus, in an INELASTIC collision, which quantity is conserved (and which is not)?As per your syllabus, eqn 5.22, in a COMPLETELY inelastic 1D collision (mass m₁ at v₁ hits m₂ at rest), the coAs per your syllabus, eqn 5.26 / 5.27, in an ELASTIC 1D collision of m₁ (v₁) with m₂ (at rest), the final veloAs per your syllabus, (2D elastic between EQUAL masses, one at rest), the two final velocities make which anglAs per your syllabus, two cars colliding and locking together (no rebound) is an example of which collision tyAs per your syllabus, during the collision interval itself, conservation of momentum holds at which moments?As per your syllabus, how many conservation equations does linear momentum yield in 3D?A 50 N force acts at right angles to a body's displacement. Work done?Work done on a load held steadily on a lifter's shoulder isWork done by a friction force that opposes the motion isThe kilowatt hour (kWh) on an electricity bill is a unit ofOne kilowatt hour equals how many joules?Kinetic energy is best described as aThe spring constant k is measured inA stiff spring is one that hasWhich of these forces is non-conservative?In every kind of collision, which quantity is conserved?Moon in a perfectly circular orbit: work done by Earth's gravity isFor gravitational PE mgh near Earth, the zero is usually atFor a spring, the zero of potential energy is at theThe work-energy theorem relates net work to the change inThe watt is the same as oneWhich steam-engine innovator gave his name to the unit of power?Which of these is a vector, not a scalar?Kinetic energy of a 2 kg body moving at 3 m/s isA 10 N force moves a body 5 m along its own direction. Work done?A block glides on a smooth desk. Work done by its weight isYou push hard against a rigid brick wall. Work done on the wall isA 1 kg mass is 10 m above the ground. Its PE is (g = 10 m/s^2)Which expression gives the dimensions of work?The instantaneous power of a force F on a body of velocity v isA machine does 3000 J of work in 10 s. Its average power isIf the speed of a body is halved, its kinetic energy becomesIf the mass doubles at the same speed, the kinetic energyA 4 kg body has 50 J of kinetic energy. Its speed isNet work done on a body is zero. Its kinetic energyA 1000 kg car going 10 m/s is braked to rest. Work done on car?A 5 N friction force opposes a body that moves 4 m. Work by friction?A cyclist skids 10 m against a 200 N stopping force. Work by road?A 20 N force at 60 degrees to the displacement moves a body 10 m. Work done?A 2 kg body rises 5 m. Work done by gravity? (g = 10 m/s^2)A body falls through height h. Work done by gravity isA 50 kg load is lifted 10 m in 5 s. Power needed? (g = 10 m/s^2)A motor lifts 100 kg at a steady 2 m/s, no friction. Power? (g = 10)A 750 W motor runs. In horse-power this is aboutA motor of 1492 W equals how many horse-power?A 2 kW heater runs for 3 hours. Energy consumed?A ball is dropped from 20 m (g = 10). Speed on hitting ground?A stone falls freely from 5 m (g = 10). Speed at the ground?A ball is thrown up at 20 m/s. Max height? (g = 10, no drag)A block slides from rest down a smooth 1.8 m slope. Speed? (g = 10)For a freely falling body, which quantity stays constant?A spring with k = 200 N/m is compressed 0.1 m. Energy stored?A spring is stretched twice as far. Its stored energy becomesA spring has k = 500 N/m. Force for 0.04 m extension?Hooke's law for a spring isA spring with a small k is calledA 2 kg body at 6 m/s sticks to a 4 kg body at rest. Final speed?2 kg at 6 m/s sticks to 4 kg at rest. Kinetic energy lost?In a head-on elastic hit between equal masses, with one at rest, the moverEqual masses collide elastically head-on, target at rest, mover at 4 m/s. Target speed after?A collision where deformation is only partly relieved isWhich quantity can change in an inelastic collision?The work-energy theorem is a scalar form ofConservation of mechanical energy follows from the WE theorem forPotential energy can be defined only forIn the WE theorem, the work that equals the change in KE is done by theA 1 g raindrop falls 1 km, landing at 50 m/s (g = 10). Work by air resistance?The centripetal force in uniform circular motion doesWork done by gravity as a stone rises vertically isWork is positive when force and displacement make an angle ofElectricity bills record consumption inWork done per unit time is calledA stretched spring can do work on release because it storesThe gravitational PE of a body turns into kinetic energy when itFor a conservative force, the change in K + V equalsA pendulum bob has maximum kinetic energy atWork in physics needs both force andA spring of constant k, extended by x, stores energyA 1800 kg lift rises at 2 m/s against 4000 N friction. Motor power? (g = 10)A motor delivers 44000 W. In horse-power this is nearlyA 4 kg body moves at 3 m/s. Its kinetic energy isWork of 100 J is done in 2 s. Average power?