UNIT 3 - WORK AND ENERGY

Question 1

WHAT IS WORK DONE ?

Answer 1

Energy transferred

Question 2

WHAT IS CONSERVATION OF ENERGY ?

Answer 2

The total amount of energy transferred between energy types must remain constant

Question 3

WHAT IS A DISSIPATIVE FORCE ?
i.e ?

Answer 3

Dissipative forces go against the motion of an object
Friction and air resistance

Question 4

HOW CAN THE SPRING CONSTANT BE FOUND ?

Answer 4

By finding the gradient of the graph

Question 5

WHAT IS EQUAL TO WORK DONE ?

Answer 5

Area under the graph is equal to work done

Question 6

WHAT IS KINETIC ENERGY ?

Answer 6

Kinetic energy is the energy an object possesses due to its motion

Question 7

WHY DO WE NEED SEAT BELTS ?

Answer 7

Designed to stop a passenger from continuing to move forward in a collision
They stretch slightly to increase to increase the distance before the stop, which reduces the force of the impact.

Question 8

WHY DO WE NEED CRUMPLE ZONES ?

Answer 8

The crumpling absorbs energy energy from the impact meaning less energy is exerted on the passenger.
Crumple zones increase the time taken for the vehicle to slow down in an impact reducing the force of the impact.

Question 9

AIR BAGS ?

Answer 9

Increases the amount of time taken for a passengers head to go from max speed to a full stop.
This reduces the deceleration which reduces the force exerted on the passenger’s head reducing the risk of injury

Question 10

WHY DO SPEED LIMITS KEEP PASSENGERS SAFE ?

Answer 10

Driving at a lower speed gives the driver more time to come to a stop - Decreases stopping time
In the event of a crash going at a lower speed means less kinetic energy which reduces the force of the impact

Question 11

HOW TO REDUCE ENERGY LOSS IN A VEHICLE ?

Answer 11

Aerodynamic losses - Using more streamlined designs, air resistance on a vehicle will be less
Rolling Losses - Can be reduced by having correctly inflated tyres, reduces friction
Inertial Losses - Reduced by using lighter materials, carbon fibre.