Forces. . .

Whenever you push, pull, stretch, squash, bend, twist or tear something you are exerting a force. A force can:

• make something move
• speed something up
• make something stop or slow down
• change the shape of things

• Some forces need to be touching to occur, while others can occur at a distance. eg. gravity

• Forces can be measured using a SPRING BALANCE. The units of force are NEWTONS.

Balanced VS Unbalanced Forces

If two forces are balanced then the object they are acting on will be either:

• stationary or
• will continue moving at a constant speed.

However, when forces are unbalanced an object will change its:

• increase or decrease it’s speed
• change it’s direction.

Forces

• We can ourselves exert forces when we push something and, by engineering, get some of the energy content in oil to produce a force on the wheels of a car to move it. From the macroscopic point of view we can imagine many different kinds of forces, forces that act at impact but also forces that act over a distance such as the gravitational one. In physics, though, we try to systematise and to find as many general concepts as possible. One such systematisation is to find out the ultimate constituents of matter. Another is to find out the forces that act between them. In the first case, we have been able to divide up matter into atoms and the atoms into nuclei and electrons, and then the nuclei into protons and neutrons.

Different Types of forces

Special Forces

 

•  In physics, force is an influence that may cause an object to accelerate. It may be experienced as a lift, a push, or a pull. The actual acceleration of the body is determined by the vector sum of all forces acting on it (known as net force or resultant force). In an extended body, force may also cause rotation or deformation of the body.

Forces summary

Makes something move

Speeds something up

Makes something stop or slow down

Changes the shape of somethings

Force Freak

A Bowling Ball

Take bowling for example.

When you are bowling the ball you are using the force of your arm to swing the ball. Then when you release the ball it is rolling using the built up force from your arm to roll, it is also encountering resistance from Gravity, Friction and Air Resistance. When the ball hits the pins it use’s impulse force to knock them over and then when it hits the pads behind the pins the resistance of the pads stop the ball from carrying on in that direction.

Impulse Forces!!

If the force applied to an object is very fast and not constant then this force is called ‘Impulse’ for example when you hit a golf ball or fire a gun.

Forces

Firstly, forces can be divided into two types

1. Direct forces, where something comes into direct physical contact with another object to make it move e.g. when you throw a stone or close a door.
2. Forces that act at a distance, there is no physical contact between the objects e.g. Gravity or a Magnetic pull/push.

 The Direction of Force Affects the Movement

If an object is moving and that object collides with another object it will change its path usually in the same direction as the object which hit it. Also if 2 people pull on a rope and one person pulls one end with a force of 20kgs and the other person pulls with a force of 15kg then the rope will move with 5kgs of force towards the person who is pulling with a weight of 20kgs. Force is measured in Newtons.

Acceleration

If a force is applied to an object then it will start to accelerate in the direction that the force is pushing it, if that force is removed then the object will stop accelerating and continue at the same speed (stay constant) until it meets some resistance then it will slow down.