**Work and Energy** - Class 9 Science CBSE ICSE

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**Work and Energy**by practicing the below questions from class 9 Science.###### An object of mass 8 kg is at a certain height above the ground. If the potential energy of the object is 400 J, find the height at which the object is with respect to the ground given g = 10 ms^{-2.}

###### The unit of power is _______.

###### Work done = Force x _______

###### Which of the following statements is not correct?

When doing a *chin-up*, a student lifts her 42.0 kg body a distance of 0.25 meters in 2 seconds. What is the power in watts delivered by the student's biceps? g = 10 ms^{-2}

###### A man of mass 60 kg runs up a flight of 60 steps in 40 seconds. If each step is 20 cm high, calculate his power.

###### What happens to a ball when it is dropped?

###### A coolie carries a load of 500 N to a distance of 100 m. The work done by him is __________.

###### A porter lifts a luggage of 10 kg from the ground and puts it on his head 1.5 m above the ground. Calculate the work done by him on the luggage in joules.

###### Mechanical energy exists in two forms. They are ____________.

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