The driver of a car traveling at a speed of 27 m/s slams on the brakes and comes to a stop in 3 s. If we assume that the speed changed at a constant rate (constant net force), what was the average speed during this 3 s interval

Average speed = 13.5 m/s

Explanation:

Since the car is running at a speed of 27 m/s  and it stops after 3 seconds by applying the brake. Therefore, the initial speed of the 27 m/s and final speed is 0.

Use below formula to find the average speed :

Average speed = (Initial speed + final speed ) / 2  

Average speed = (27 + 0 ) / 2

Average speed = 13.5 m/s

the displacement produced by the body.  

the amount of force subjected to the body.  

the angle between the direction of force and displacement

measuring things 1 litre of water