Name two sports that are played by changing the speed and direction of motion of objects.

Some of the facts that you have learnt till now are listed below. Tick (✓) the facts that are correct and cross (x) the facts that are incorrect.

(a) Force can only change the direction and motion of a body.

(b) The SI unit of force is newton.

(c) The resultant force is the total force acting on a body.

(d) A lot of force can change the mass of a body.

(e) The body only moves if the applied force is sufficient.

Write one word or few words for the following.

(a) This contact force comes into play when two bodies collide

(b) This force attracts iron and nickel towards the magnet

(c) Friction is reduced on this surface

(d) This type of friction exists when the two bodies are at rest

(e) This type of friction is more than rolling friction

Why do wrestlers and gymnasts rub powder/chalk on their hands?