work and energy

Question 1

work done

Answer 1

the energy transferred is known as the work done

Question 2

equation of work done

Answer 2

w=fd
d = distance moved in the direction of the force

Question 3

how can you find the spring constant from a graph

Answer 3

by finding the gradient

Question 4

ways that a vehicles efficiency can be improved

Answer 4

Vehicles’ efficiency can be improved in many ways, including the following:

reducing aerodynamic losses due to air resistance
rolling resistance due to friction between the tyres and the road
idling losses due to the engine using fuel when the vehicle is stationary
inertial losses due to the fuel used when accelerating.

Question 5

aerodynamic

Answer 5

Aerodynamic losses can be reduced by using more streamlined designs; this means the air resistance acting on the vehicle will be less.

Question 6

rolling

Answer 6

Rolling losses can be reduced by having correctly inflated tyres. Vehicle designers work to reduce these losses by including sensors in the tyres to monitor the tyre pressure and warn the driver if the pressure is not correct.

Question 7

idling

Answer 7

Idling losses occur when a vehicle is stationary in traffic or waiting at a red light, the engine is still running and is using fuel. Start-stop systems automatically stop and restart the engine to reduce this.

Question 8

inertial losses

Answer 8

Inertial losses are reduced by using lighter materials in the construction of vehicles. For example, lighter carbon fibre is used instead of heavier metals for certain car parts.

Question 9

what happens when you improve the efficiency of a car

Answer 9

By improving the efficiency of vehicles, they will use less fuel to travel the same distance. This has two main advantages.

Using less fuel means that the cost of a journey is reduced.
Burning less fossil fuel reduces the greenhouse gasses produced which cause global warming.

Question 10

how do we reduce the impact of the injury on a person

Answer 10

The design of modern cars includes many safety features that reduce the chance of severe injury in a collision. These include seat belts, air bags and crumple zones.

Seat belts are designed to stop a passenger continuing to move forward in a collision; they also stretch slightly.

Crumple zones are areas of a car which change shape or compresses during a collision.

Air bags deploy to the front and sides of a passenger in a collision.

Each of these features increase the distance over which the energy of the passenger is transferred; this reduces the force of the impact on the passengers.