forces - force and braking

Question 1

any moving object has…

Answer 1

kinetic energy

Question 2

kinetic energy equation

Answer 2

Ek=1/2 x m x v squared
kinetic energy= 1/2 x mass (kg) x velocity (m/s)

Question 3

what does kinetic energy depend on?

Answer 3

velocity squared.
example: if we double velocity of the car, kinetic energy quadruples

Question 4

what happens to kinetic energy when a car brakes and comes to a stop

Answer 4

it is converted to other forms of energy.

Question 5

what happens to the brakes during braking?

Answer 5

the brake presses against the wheel. the force of friction now acts between brake and wheel. kinetic energy converted to thermal energy in brakes causing temperature of brakes to increase. at the same time, car slows down as it looses kinetic energy

Question 6

the greater the speed….

Answer 6

the greater the braking force needed to stop the car in a certain distance

Question 7

what does the driver have to do if car is going at high speeds and needs to brake? what happens during this?

Answer 7

apply a very large braking force. this large braking force will cause a car to decelerate rapidly. at the same time, a large amount of kinetic energy is transferred to thermal energy in the brakes which can cause brakes to overheat and/or driver to lose control of the vehicle

Question 8

force equation

Answer 8

mass (kg) x acceleration (m/s squared)