Question

Classify each force as contact or non-contact: (a) a player kicking a football (b) the Earth pulling a falling mango (c) a magnet pulling a steel paper clip from a distance (d) friction slowing down a rolling bicycle.

At a school science fair, Kabir shows two experiments. In the first, he brings a bar magnet near a few steel pins lying on a table; the pins jump up and stick to the magnet before touching it. In the second, he rubs an inflated balloon on his woollen sweater and holds it near a thin stream of water from a tap; the stream bends towards the balloon.