Work And Energy

The unit of work is joule. The other physical quantity that has same unit is:
1. Power
2. Velocity
3. Energy
4. Force
The spring will have maximum potential energy when:
1. It is pulled out
2. It is compressed
3. In both cases
4. None of the cases
The energy possessed by an oscillating pendulum of a clock is:
1. Kinetic energy
2. Potential energy
3. Restoring energy
4. Mechanical energy
The gravitational potential energy of an object is due to:
1. Its mass
2. Its acceleration due to gravity
3. Its height above the earth's surface
4. All of these
A ball is dropped from a height of 10 m.
1. Its potential energy increases and kinetic energy decreases during the falls
2. Its potential energy is equal to the kinetic energy during the fall
3. The potential energy decreases and the kinetic energy increases during the fall
4. The potential energy is 0 and kinetic energy is maximum while it is falling
If the velocity of a body is doubled its kinetic energy:
1. Gets doubled
2. Becomes half
3. Does not change
4. Becomes 4 times
How much time will be required to perform 520 J of work at the rate of 20 W?
1. 26 s
2. 16 s
3. 20 s
4. 24 s
A students caries a bag weighing 5 kg from the ground floor to his class on the first floor that is 2 m high. The work done by the boy is:
1. 1 J
2. 100 J
3. 10 J
4. 1000 J
The work done is 0 if:
1. The body shows displacement in the opposite direction of the force applied
2. The body shows a displacement in perpendicular direction to the force applied
3. The body shows displacement in the same direction as that of the force applied
4. The body masses obliquely to the direction of the force applied
One unit of electrical energy is equal to:
1. $3.6 \times 10^{5} J$
2. $3.6 \times 10^{6} J$
3. $36 \times 10^{5} J$
4. None of these
When a body falls freely towards the earth, then its total energy:
1. Decreases
2. Increases
3. First increases and then decreases
4. Remains constant
When a body like earth is moving in a circular path the work done in that case is zero because:
1. Centripetal force acts in the direction of motion of the body
2. Centripetal force acts along the radius of circular path
3. Gravitational force acts along the radius of circular path
4. Centrifugal force acts perpendicular to the radius of circular path
A car is accelerated on a leveled road and attains a velocity 4 times of its initial velocity. In this process, the kinetic energy of the car:
1. Becomes twice to that of the initial
2. Becomes four times to that of the initial
3. Remains the same
4. Becomes 16 times to that of the initial
The momentum of a bullet of mass 20 g fired from a gun is 10 kg m/s. The kinetic energy of this bullet in kJ will be:
1. 25
2. 2.5
3. 0.25
4. 5
Which one of the following is not the unit of energy?
1. Kilowatt
2. Kilowatt hour
3. Joule
4. Newton metre
The form of energy possessed by a flying bird is:
1. Kinetic energy
2. Potential energy
3. Both kinetic and potential energy
4. Can't say
In the dams water is stored in the high reservoirs and then made to fall down. This falling water then rotates the turbines to generate electricity. In this energy conversion process can you tell the initial and final energies respectively?
1. Kinetic energy and electrical energy
2. Potential energy and kinetic energy
3. Potential energy and electrical energy
4. Kinetic energy and potential energy
A man of mass 50 kg jumps to a height of 1 m. His potential energy at the highest point is (g = $10 m / s^{2}$ ):
1. 50 J
2. 500 J
3. 5 J
4. 5000 J
The type of energy possessed by a simple pendulum, when it is at the mean position is:
1. Kinetic energy
2. Potential energy
3. Kinetic + Potential energy
4. Sound energy
A body is falling from a height h. After it has fallen to a height of $\frac{h}{2}$ , it will possess:
1. Only kinetic energy
2. Half kinetic and half potential energy
3. Only potential energy
4. More kinetic and less potential energy
Two objects of masses $1 \times 10^{- 3} k g$ and $4 \times 10^{- 3} k g$ have equal momentum. What is the ratio of their kinetic energies?
1. 2 : 1
2. 4 : 1
3. 1 : 4
4. 1 : 2
The work done on an object does not depend upon the:
1. Angle between force and displacement
2. Force applied
3. Initial velocity of the object
4. Displacement
An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are 10 m above the ground, they have the same:
1. Potential energy
2. Momenta
3. Acceleration
4. Kinetic energy
A microphone converts:
1. Sound energy into mechanical energy in stereo system
2. Sound energy into electrical energy in public address system
3. Electrical energy into sound energy in ordinary telephone
4. Microwave energy into sound energy in a mobile phone
Which of the following energy change involves frictional force?
i. Potential energy to sound energy
ii. Chemical energy to heat energy
iii. Kinetic energy to heat energy
iv. Chemical energy to heat energy
Choose the correct option among the following:
1. Both (i) and (ii)
2. Only (iv)
3. Both (ii) and (iii)
4. Only (iii)
In case of negative work the angle between the force and displacement is:
1. $0 °$
2. $45 °$
3. $90 °$
4. $180 °$
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 = $10 m / s^{2}$ ):
1. Zero
2. 6 J
3. 0.6 J
4. 60 J
A rocket is moving up with a velocity v. If the velocity of this rocket is suddenly tripled, what will be the ratio of two kinetic energies?
1. 1 : 3
2. 1 : 9
3. 3 : 1
4. 9 : 1
Avinash can run with a speed of 8 m/s against the frictional force of 10 N, and Kapil can move with a speed of 3 m/s against the frictional force of 25 N. Who is more powerful?
1. Avinash
2. Kapil
3. Both are of equal power
4. Can't say
A boy is moving on a straight road against a frictional force of 5 N. After travelling a distance of 1.5 km he forgot the correct path at a round about of radius 100 m. However, he moves on the circular path for one and half cycle and then he moves forward upto 2.0 km. Calculate the work done by him.
1. 20000 J
2. 19000 J
3. 18500 J
4. None of these

Work And Energy

Quiz