Measuring+Forces

=Measuring Forces: Gravity=

How hard can you pull? We can measure the strength of a force with a forcemeter. The unit of force is Newton (N), named after Issac Newton, an english physicist who studied forces. One force he was particulary interested in was gravity. Gravity is the force that pulls masses(Matter) together. The greater the mass, the greater the force. Planet Earth is a large mass. It pulls a 100g objects (such as a green apple) at the surface of the Earth with a force of 1N. We say the weight of a green apple is 1N. WEIGHT:Is the force of gravity on a mass** Mass is the same where ever you are, but weight depends on the gravity force at the place. The Moon is much smaller than the Earth. On the Moon a 100g green apple would have a weight of only 0.16N
 * MASS: The amount of matter there is.

Measuring Force We can measure a force and we use a specific unit to do so. It is called a //Newton//. This measurement is called an //SI UNIT//, which stands for Systeme International. This means it is an internationally recognised term for a whole range of metric measurements which was accepted in 1960.

Mass Mass is represented by //m// in science - but what is it? It is the amount of matter in an object. Imagine looking at a piece of ordinary chocolate and an a piece of Aero. If the two pieces were exactly the same size and you were to predict which would be the heavier I am sure you would go for the ordinary chocolate. This is because, for the same size, the matter in it is more closely packed. You could say the same about a piece of polystyrene and a block of wood of exactly the same volume, or any number of other materials. When we want to measure Mass we do so using //grams// or //kilograms//. For some this can cause confusion because we normally associate grams or kilograms with weight. BUT as we have said earlier //Newtons// are used to measure Force, and since Weight is a downward force caused by Gravity, weight is measured in //Newtons// It should also be remembered that the Mass of an object is constant whereas the weight of an object can change in Gravity, and this will be affected by where the object is in relation to other objects. For instance, your weight on the Moon would be approximately one sixth of your weight on earth due to the effect of Gravity.

Speed Speed is the rate at which an object moves in a straight line or in a continuous curve. If we wish to find out the speed of an object and we know the distance travelled and the time taken we can use the following formula:

For instance, if we know the distance travelled is 180 kilometres and the time taken is 2 hours then: SPEED = 90 km/h Similarly we can use the formula to find out other aspects: DISTANCE = SPEED TIMES TIME AND TIME = || __DISTANCE__ ||
 * SPEED = || __DISTANCE__ ||
 * ^  || TIME ||
 * SPEED = || __180 km/h__ ||
 * ^  || 2 hrs ||
 * ^  || SPEED ||