EASY
9th CBSE
IMPORTANT
Earn 100

A car with K.E.100J is moving on a horizontal road. Now 200J work is done on the car. The change in K.E. is

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Important Questions on Work and Energy

MEDIUM
9th CBSE
IMPORTANT
Two bodies with kinetic energy in the ratio of 4:1 are moving with equal linear momentum. The ratio of their masses is 
EASY
9th CBSE
IMPORTANT
A car of mass one metric ton accelerate from rest at the rate of 2m/s2 from t=0 sec to t=10 s. Thereafter it travels with a uniform velocity. The measure of net retarding force acting on the car after 10 s is
EASY
9th CBSE
IMPORTANT
 A certain household has consumed 200 units of energy during a month. Its value in joules will be
EASY
9th CBSE
IMPORTANT

A person of mass 50kg runs up to the staircase of 40  steps in 6 s. If the height of each step is 15cm, then his power will be (If g=10m/s2).

MEDIUM
9th CBSE
IMPORTANT
If mass is doubled and velocity is halved then, new kinetic energy is
EASY
9th CBSE
IMPORTANT

Devender was going to buy a tungsten filament bulb. His son Raghav told not to buy that bulb. He suggested to buy a CFL which consumes much less power than the tungsten filament bulb. Divya also joined teh discussion and requested her dad to buy a LED bulb which did not create pollution as created by CFL and had much greater life span than CFL.

Question Image

Answer the following question:

What is power?

EASY
9th CBSE
IMPORTANT

Devender was going to buy a tungsten filament bulb. His son Raghav told not to buy that bulb. He suggested to buy a CFL which consumes much less power than the tungsten filament bulb. Divya also joined the discussion and requested her dad to buy a LED bulb which did not create pollution as created by CFL and had much greater life span than CFL. 

Question Image

Answer the following question:

Why tungsten filament bulb consumes more power?

EASY
9th CBSE
IMPORTANT

Ramesh, son of a wealthy farmer and a student of Class IX lived in a small village. One day he went on an educational trip where he saw solar cell panels used for street light. When he returned from the trip, he shared this information with his father and requested him to install a solar panel to light the backyard of their house as it could save electricity bill.

Name the energy transformation taking place in a solar cell panel.