Question

SECTION I [40 marks]
Attempt all questions from this section. Question 1
(a) A body is acted upon by a force. State two conditions when the work done is zero. (b) Calculate the height through which a body of mass 0.5 kg is lifted if the energy spent in doing so is 1 J (Take g = 10 ms–2). (c) Compare the K.E. of a moving body if its velocity becomes halved.
(d) Which physical quantity is measured in eV? How is it related to the SI unit of that quantity?
(e) State the energy changes in the following devices while in use: (i) electric motor. (ii) microphone.
Question 2
(a) A tennis ball and a table tennis ball have the same momentum. Which of the two has more K.E. and why?
(b) State two conditions for a body, acted upon by several forces, to be in equilibrium. (c) A spanner (or wrench) has a long handle. Why?
(d) State a factor on which the position of the centre of gravity of a body depends. Explain your answer with an example. (e) Is it possible to have an accelerated motion with a constant speed? Name such type of motion.​

Answer 1

Explanation:

An atmosphere is a layer or a set of layers of gases surrounding a planet or other material body, that is held in place by the gravity of that body. An atmosphere is more likely to be retained if the gravity it is subject to is high and the temperature of the atmosphere is low

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