Question

A car is speeding at 25m/s the brakes abruptly bring the 500kg car to a speed of 3m/s over a distance of 5m determine the force applied by the brakes and the work done by the braking forcevon the car

Answer 1

work done = change in KE

change in KE = 1/2 m (v2-u2)

1/2 x 500 x (625-9)

work done = 1/2 x 500 x (625-9)

= 154000 J

that's your answer

Answer 2

Hey mate,

Water is a good conductor of electricity. So, if the electrical supply for the area is not shut off and water is spread over electrical appliances, then electricity may pass through water and harm the firemen. Therefore, in case of a fire, the firemen shut off the main electrical supply for the area before they use the water hoses.

Hope it helps...