Which one of the following is not the unit of energy?
  • joule
  • newton metre
  • kilowatt
  • kilowatt hour
When a body falls freely towards the earth, then its total energy
  • increases
  • decreases
  • remains constant
  • first increases and then decreases
A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the potential energy of the car
  • does not change
  • becomes twice to that of initial
  • becomes 4 times that of initial
  • becomes 16 times that of initial
In case of negative work the angle between the force and displacement is (NCERT Exemplar)
  • 0°
  • 45°
  • 90°
  • 180°
An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass is5 kg. Both spheres are dropped simultaneously from a tower. When they are lo m above the ground, they have the same.
  • acceleration
  • momenta
  • potential energy
  • kinetic energy
A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g = 10 ms²)
  • 6 × 10³ J
  • 6 J
  • 0. 6 J
  • zero
The work done on an object does not depend upon the
  • displacement
  • force applied
  • angle between force and displacement
  • initial velocity of the object
Water stored in a dam possesses
  • no energy
  • electrical energy
  • kinetic energy
  • potential energy
A body is falling from a height h. After it has fallen a height \(\frac{h}{2}\), it will possess
  • only potential energy
  • only kinetic energy
  • half potential and half kinetic energy
  • more kinetic and less potential energy
Two army persons A and B each of weight of 500 N climb up a rope through a height of 10 m. A takes 20 s while B takes 40 s to achieve this task. What is ratio of the powers of person A and B?
  • 1 : 2
  • 1 : 4
  • 2 : 1
  • 14 : 1
If speed of a car becomes 2 times, its kinetic energy becomes
  • 4 times
  • 8 times
  • 16 times
  • 12 times
Work done by friction
  • increases kinetic energy of body
  • decreases kinetic energy of body
  • increases potential energy of body
  • decreases potential energy of body.
When a coil spring is compressed, the work is done on the spring. The elastic potential energy
  • increases
  • decreases
  • disappears
  • remains unchanged
One joule work is said to be done when
  • a force of 1 N displaces a body by 1 cm
  • a force of 1 N displaces a body by 1 m
  • a force of 1 dyne displaces a body by 1 m
  • a force of 1 dyne displaces a body by 1 cm.
SI unit of power is
  • watt
  • joule
  • newton
  • metre
Mechanical energy of a body includes
  • kinetic energy only
  • potential energy only
  • kinetic energy and potential energy
  • none of these
Commercial unit of energy is
  • joule
  • kWh
  • watt
  • newton
Potential energy of a body depends on its
  • position
  • configuration
  • position and configuration
  • mass and velocity
A force of 50N on a body causes a displacement 20 m in the direction of the force.What is the workdone by the force?
  • A. 100J
  • B. 1000J
  • C. 2.5J
  • D. None of these
A pump takes 20 sec to lift 100 kg of water to the water tank situated at the height of 10 m. What is the power of the pump? Given g=10m/s-2
  • A. 2 Kilowatt
  • B. 1 kilowatt
  • C. 1.5 kilowatt
  • D. .5 kilowatt
0 h : 0 m : 1 s

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