FORCE

What is force? Well, it's really simple. It's something that produce changes in motion of an object, and force is simply a push or pull. When you talk about force, you got to know about the three main parts of the FORCE:

• Balance force
• Directions of forces
• Feasuring forces

BALANCE FORCE

 Look at the photograph of the bridge at the left. The bridge doesn't look like any force is acting on it. Because there are no obvious changes. But however, there are forces acting on the bridge. But the effect of all the different forces cancel out. The bridge remains stationary because all the forces on it are exactly balanced. There is no total force acting on the bridge.
 The parachutist at the right is moving down at a constant speed. Moving at a constant speed, so the forces acting must be balanced. The downward force (call the weight) of the parachutist and the equipment is balanced by an upward force due to air resistance.

DIRECTION OF FORCES

The arrows are the forces that acts on the perachutist which also points to the direction of the force. We can't find out if the forces are balanced. However, we know the direction in which are acted. For any force, it is necessary to know both its size and the direction in which it acts. There are two types of quantity in scientific measurement: SCALAR and VECTOR .

A vector quantities must have direction, size and units. Vector quantities are often seen when we talk about force.

Here is an example of the importance of knowing directions. A car drove 30 km, stop and then drove 15km. How is the car away from the starting position? There is no way of knowing unless you know the direction in which the car was moving. In order to solve the problem, a question like "A car drove 30 km due north, stops and then drove 15 km east".

All forces are vector quantities, it is very important to show the directions in which they act.

MEASURING FORCES

Apart from knowing the direction in which a force acts, it is necessary to know it's size also. All force are measured in units called Newtons.The symbol for the Newton is N. The unit is named after Sir Isaac Newton. One of his great discoveries was the law of gravitation. Gravity is the force that pulls us toward the surface of the earth. This force is usually called the weight of the object. Newton's law allows us to calculate the size of this force

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