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प्रश्न
Explain, why submarines are able to dive underwater as well as a sail on the surface of the water?
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उत्तर
Submarines are provided with ballast tanks. When required to dive, the water is allowed to enter the tanks. And when required to sail, the water is forced out by compressed air.
Work is a scalar quantity.
संबंधित प्रश्न
Work is said to be done by a forte only when ................
Define 1 joule of energy.
A body of mass 5 kg falls from a height of 10 m to 4 m. Calculate:
The loss in potential energy of the body,
Fill in the blank with suitable word :
Work is measured as a product of __________ and __________
A machine raises a load of 750 N through a height of 16 m in 5s. calculate:
(i) work done by machine,
(ii) power at which the machine works.
A boy pulls a box up to 10 m with a force of 5 kgf. Calculate the work done by him.
Calculate the amount of work done by a child carrying a bag of 20 kg when he moves a distance of 40 m in
(a) Vertical direction, and
(b) Horizontal direction
Give an example
Chemical energy changes to heat energy.
A body of mass 60 kg has the momentum 3000 kgm/s-1. Calculate: the speed of the body.
A girl of mass 40 kg runs a height of 80 stairs, each 25 cm high with a load of 20 kg on her head in 25 sec. If g is 10 m/s2, find:
(i) Gravitational force acting on the girl.
(ii) Work done by her.
(iii) Useful work done by her.
(iv) Her power in watt.
