4 Ambulance ACTION You can hear an ambulance coming from far away Its siren blares and blares Then you can see its flashing lights If you’re in another car you have to get out of the way and let the ambulance pass It may be heading for a hospital carrying a sick or injured person or perhaps dashing to the site of an accident Today they can also be equipped with sophisticated medical equipment and have specially trained emergency medical staff on board What force keeps the ambulance passengers safe
Most ambulances have to carry specific bits of equipment that can be used in emergency situations This includes materials for breathing failure heart disorders burns and broken bones Ambulances also carry gases such as oxygen Modern ambulances include a sophisticated electronic program controlled by sensors This keeps the ambulance balanced and steady even when it is travelling quickly or turning corners at high speed It guarantees a safer and more comfortable ride for the patient inside ANSWER EQUILIBRIUM An ambulance must be able to adjust its balance constantly to cope with the different forces that push and pull at the vehicle as it moves This means the ambulance needs to remain equally balanced or in equilibrium If a force acts on an object and it doesn’t move it means there must be another force acting on it from another direction The two equal forces are balancing each other out This describes the balanced position known as equilibrium (cid:2) (cid:2) (cid:2) (cid:2) equilibrium or equal forces (cid:2) (cid:2) (cid:2) (cid:2) 5
6 A wrecker crane is made up of a lever with a hook attached to the end A lever is a kind of machine that can be controlled by a motor or other means to lift a heavy weight What happens if your car breaks down while it’s travelling on the road You might call an automobile club who’ll send someone out to try and fix the problem But if it can’t be fixed the car has to be moved So you need a wrecker to come and haul it away Wreckers have a crane on the back that is used to raise the front end of a stranded car Depending on the type of truck they can lift anything from a mini car to a bus or even another truck Wrecker ACTION What simple machine helps the truck do its work
ANSWER LEVER A lever is a simple machine with a fulcrum a load and an effort a push or pull A force used to move one end of the lever will lift a load at the other end The closer the fulcrum is to the load the less effort is needed to lift it There are three different kinds of lever depending on where the fulcrum is placed The crane is lowered and raised by a third class lever This has the fulcrum at one end the effort in the middle and the load at the other end effort fulcrum load The lever is pushed in the middle by an hydraulic ram a kind of plunger inside a tube that is moved in and out by the pressure of a liquid 7
