A car moving at 20 m/s crashes into a bridge abutment. Calculate the magnitude of the average force on a 60 kg driver if the car stopped over a period of 2 seconds by crashing into a row of water filled barrels.

Explanation:

Step one:

given data

velocity = 20m/s

mass m= 60kg

time t= 2 seconds

The impulse is the force acting instantly

the expression for impulse is

Ft=mv

F=mv/t

substituting we have

F=60*20/2

F=1200/2

F=600N

Therefore the average force is 600N

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.