[1 mark/markah]
(f) explain the effect on human being if exposed to radioactive ray for longer period.
terangkan kesan terhadap manusia jika terdedah kepada sinaran radioaktif untuk jangka masa yang
panjang?
[2 marks/markah)

Abatter hits a 0.140-kg baseball that was approaching him at 30 m/s and, as a result, the ball leaves the bat at 40 m/s in the reverse of its original direction. the ball remains in contact with the bat for 2.0 ms. what is the magnitude of the average force exerted by the bat on the ball?