What is the average friction force when a person has a usual 1 km walk?

Find the average frictional force needed to stop a acar wieghing 500 kg in a distance of 25 m i the initial speed is 72 km/h.

When a person walks on a rough surface .

The average speed of a person in driving to school is 30 km//h . On the return trip along the same rout, the average speed is 25 km//h . What is the average speed for the round trip to the school ?

When a person walks on a rought surface, the frictional force exerted by surface on the porson is opposite to the direction of his motion. It is the force exerted by the road on the person that causes the motion.

Which of the following is correct , when a person walks on the rough surface.