CTET Class I to V 2012 Nov Paper

While discussing about friction, a teacher gave a number of examples to explain the concept. Some of the examples where friction is useful in our day-to-day life as quoted by the teacher are given below:
1. We are able to write because of friction between the tip of the pen and the paper.
2. We are able to walk because of friction between our feet and the ground.
3. A ball thrown vertically upwards comes back to us due to friction.
4. We are able to stop a moving vehicle by applying brakes because of friction.
The correct examples were