Q50 of 146 Page 145

What type of energy is possessed?

(a) By the stretched rubber strings of a catapult?


(b) By the piece of stone which is thrown away on releasing the stretched rubber strings of catapult?

a) A stretched rubber string posses potential energy as there is no motion.

b) The stone posses kinetic energy as it posses motion.


More from this chapter

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48

If the work done by a force in moving an object through a distance of 20 cm is 24.2 J, what is the magnitude of the force?

 49

A boy weighing 40 kg makes a high jump of 1.5 m.

(i) What is his kinetic energy at the highest point?


(ii) What is his potential energy at the highest point? (g = 10 m/s2).

 51

A weightlifter is lifting weights of mass 200 kg up to a height of 2 metres. If g = 9.8 m/s2, calculate:

(a) Potential energy acquired by the weights.


(b) Work done by the weightlifter.

 52

Define the term ‘work’. Write the formula for the work done on a body when a force acts on the body in the direction of its displacement. Give the meaning of each symbol which occurs in the formula.