Work and Energy — Science STD 9 — Question

(1) Dr N. Gopinath – open heart surgery
(2) Ramchandra Sharma – a skilled craftsman
(3) Dr Subhash Mukhopadhyaya – test tube baby
(4) Dr Mohan Rao – polio (write the wrong pair)

What are the different things included in solid waste ?

Raj applied a force of 20 N and moved a book 40 cm in the direction of the force. How much was the work done by Raj?

A stone having a mass of 250 gm is falling from a height. How much kinetic energy does it have at the moment when its velocity is 2 m/s?

1 kg mass has a kinetic energy of 2 joule. Calculate its velocity.

State any four uses of concave mirror.

A force of 50 N acts on an object and displaces it by 2 m. If the force acts at an angle of 60° to the direction of its displacement, find the work done.

What are basic organic compounds? What are they also called as?

Hydrogen gas is filled in two identical bottles, A and B, at the same temperature. The mass of hydrogen in the two bottles is 12 gm and 48 gm respectively. In which bottle will sound travel faster? How may times as fast as the other?

Which device converts electrical energy into heat?