work , energy power

A car is accelerated on a lavelled road and attains a velocity 4 times of its initial velocity. Inthis process,the potential energy of the car

(a) does not change

(b) becomes twice to that of initial

(c) becomes 4 times that of initial

(d) becomes 16 times that of initial

• a

• b

• c

• d

An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass 3.5kg. Both spheres are dropped simultaneously from a tower. When they are 10 m above the ground, they have the same

(a) acceleration

(b) momenta

(c) potential energy

(d) kinetic energy

• a

• b

• c

• d

When a body falls freely towards the earth, then its total energy

(a) increases

(b) decreases

(c) remains constant

(d) first increases and then decreases

• a

• b

• c

• d

In case of negative work, the angle between the force and displacement is

(a) 0

(b) 45°

(c) 90°

(d) 180°

• a

• b

• c

• d

Water stored in a dam possesses

(a) no energy

(b) electrical energy

(c) kinetic energy

(d) potential energy

• a

• b

• c

• d

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/s² )

(a) 6 x 10 J

(b) 6 J

(c) 0.6 J

(d) zero

• a

• b

• c

• d

The work done on an object does not depend upon the

(a) displacement

(b) force applied

(c) angle between force and displacement

(d) initial velocity of the object

• a

• b

• c

• d

The power of a motor pump is 2 kW. How much water per minute, the pump can raise to a height of 10 m? [given, g = 10 m/s² ]

• 360 kg

• 1200 kg

• 330 kg

• 430kg

Which one of the following is not the unit’ of energy?

(a) Joule

(b) Newton metre

(c) Kilowatt

(d) Kilowatt hour

• a

• b

• c

• d

If an electric iron of 1200 W is used for 30 min everyday, find electric energy consumed in the month of April.

• 4.5 X 10⁶ J

• 42.5 X 10⁷ J

• 6.4 X 10⁷ J

• 5.8 X 10⁶ J