P3 9-16

Question 1

What will make an objects kinetic energy increase?

Answer 1

If the object has a greater mass or a higher speed

Question 2

What is fuel used for in a car?

Answer 2

The fuel is burned inside the engine of the car. The heat released is converted into kinetic energy, to drive the car forwards, and electrical energy to power the radio, headlights and other electrical devices inside the car.

Question 3

What does fuel consumption depend on?

Answer 3

• Energy needed to increase the kinetic energy of the
car. This depends on the mass of the car and its contents. The greater the mass, the more fuel is required.
• Work done against resistive forces such as friction and air resistance.
• Speed and driving style of the driver. Rapid acceleration increases the amount of fuel used.
• Road conditions. Driving in heavy rain tends to lead to more fuel being consumed per mile.

Question 4

How do electrical vehicles work? Advantages and disadvantages?

Answer 4

How do they work? These store energy in large batteries which power the car. Instead of an engine, they have an electric motor which drives the car forward.

Advantages? As there is no burning involved, electric cars do not produce any pollution in the places where they are used.

Disadvantages? When the batteries run low, they must be recharged. As most of the electricity in the UK is produced by burning fossil fuels in power stations, powering an electric car still causes pollution, just not where the car is being used.

Question 5

How do solar powered cars work? Advantages and disadvantages?

Answer 5

How do they work? have batteries which can be recharged directly from the Sun. They store enough energy during the day to allow the car to be driven at night.

Advantages? Over the lifetime of a solar-powered car though, and even of a simpler electric car, less carbon dioxide might be emitted compared with a traditional car. This could lead to a reduction in our overall carbon dioxide emissions.

Disadvantages? Even though these cars do not pollute when they are being used, pollution is still produced when they are manufactured.

Question 6

What makes something have greater momentum?

Answer 6

The greater the mass or velocity of an object, the more momentum it has.

Question 7

What effect will a change in momentum in a short time have on the forces on the object and declaration?

Answer 7

The forces on an object can be very large, and the deceleration will also be very high.

Question 8

What happens during a car crash?

Answer 8

there is a sudden change in momentum. A large force can be exerted on passengers by rapid deceleration, causing injuries.

Question 9

How does a seatbelt work in a crash? Collision energy?

Answer 9

Stretches, rather than holding a passenger completely rigid.

Collision energy?Used to stretch the seatbelt bres.

Question 10

How does a crumple zone work? Collision theory?

Answer 10

Bends, absorbing some of the energy of the collision rather than resisting it as a stiffer piece of metal would.
Collision energy? Used to bend the metal in the crumple zone.

Question 11

How does an airbag work? Collision energy?

Answer 11

Creates an air filled cushion to slow the passenger gently, ensuring they don’t hit the solid steering wheel or car interior.

Collision energy? Used to slowly force the gas in the air bag out once the passenger has hit it.

Question 12

How does a collapsible steering column work? Collision energy?

Answer 12

Bends, absorbing some of the energy of the collision rather than resisting it as a completely rigid steering column would.
Collision energy? Used to bend the steering column.

Question 13

How do anti lock braking system brakes prevent accidents?

Answer 13

Helps to stop the wheels of a car locking into a skid when too much force is applied by the driver, making sure the wheel remains in contact with the road.

Question 14

How does traction control prevents accidents?

Answer 14

Compensates for any differences between the grip of the car’s four wheels on the road surface, such as when one wheel hits some ice. Loss or differences in grip of one wheel of a car can lead to the driver losing control.

Question 15

How do electric Windows prevent accidents?

Answer 15

Stop a driver being distracted by winding a window handle, and reduce the amount of time the driver’s hands need to be off the wheel.

Question 16

How do paddle controls prevent accidents?

Answer 16

Found around the steering wheels of cars, these are usually used to control the radio or sometimes to change gear. They reduce the amount of time drivers need to take their hands off the wheel, and prevent the driver looking away from the road at the radio display while driving.

Question 17

How do ABS brakes work?

Answer 17

ABS brakes help drivers control cars in hazardous situations. They sense that the wheels are about to lock and reduce the pressure on the brake pads for a fraction of a second, so that the wheel can keep moving. They then reapply the pressure. ABS brakes pump on and off like this repeatedly until the vehicle stops. ABS brakes can reduce stopping distances on dry and slippery surfaces. In some cases (such as on loose surfaces like gravel) they increase the stopping distance but can improve control of the vehicle.

Question 18

How do car safety features reduce the forces acting in a collision?

Answer 18

• increasing the time taken for the vehicles to stop, or the time taken for the collision to happen
• increasing the stopping distance of vehicles
• decreasing the acceleration of vehicles.

Question 19

What is drag?

Answer 19

When something is falling through the air, there is a frictional force in the opposite direction due to air resistance, called ‘drag’. As the speed increases, the size of the opposing drag force increases.

Question 20

What happens when an object travels though a fluid such as air or water?

Answer 20

there is a drag force on the object due to friction. The faster an object moves through the uid, the greater the frictional force which acts on it in the opposite direction.

Question 21

What is terminal speed?

Answer 21

When the speed and so the drag increase to a point where the objects weight is balanced by the upward drag force. The resultant force is zero and the object will not accelerate any more and fall at the same speed. This steady speed is called terminal speed.

Question 22

How does shape affect drag ( and so terminal speed)?

Answer 22

The larger the area, the greater the drag.

Question 23

What is gravitational potential energy?

Answer 23

the energy it has because of its position in a gravitational field, like the one around the Earth. This energy depends on the mass of the object, its height above the ground and the strength of the gravitational field.

Question 24

Describe what happens to gpe and kinetic energy in roller coasters?

Answer 24

When roller-coaster cars move over large drops, their GPE is converted into kinetic energy. Bigger drops cause a larger change in GPE. They provide a greater increase in kinetic energy and so larger drops cause the cars to move much faster. The opposite happens when the cars go up the slopes. Here the kinetic energy of the cars is converted back to GPE as they climb higher above the ground.