tell me all you know about force. (The Physics kind...)?

Question

Big test tomorrow... I don't know crap about this!

Answer 1

Formal Definition: Force is an external agency which overcoes inertia.

Lets say there your car is standing on the road. Unless you start the engine and press the accelerator peddle, you cannot see it moving, right? What actually are you doing when press the accelerator peddle? I think you can guess that you are "accelerating" it. This acceleration will make the it move. The product of the acceleration and the mass of the car will give you the force applied on the car (F=M*a). This 'force' is not something internal; it is coming from an extra fitting called the engine. You have made the car to break away from its inertia and start moving through an 'external agency'. This 'external agency' is the force applied on the car.

After sometime the speed of the car will reach a constant value, say 60mi/hr. Now you decide to fill fuel in the next station. For this you have to stop the car and you press the break peddle. The car stops after a few seconds. What has happened? When you applied brakes, the car's speed startted decreasing i.e. the car started to 'decelerate'. The product of this deceleration (-ve accelaration) and the mass of the car will give you the force applied on the car to stop it.

But actually, you can stop the car just by switching off the engine (without applying the brakes). This is because of the frictional forces that are acting between the tyres and the roads. If there were no friction, the car would move infinitely (we call it inertia). To free the car from its 'inertia', you need an 'external agency' through the brakes. This 'external agency' is called force.

Answer 2

Most important fact for solving force problems:

Net Force = Sum of forces acting on an object.

mass * net acceleration = force 1 + force 2 + etc...

In two dimensions:

x-force = sum of x-component forces (pulling, pushing, friction)
y-force = sum or y-component forces (normal force, gravity etc.)

Net force = vector sum of x-forces and y-forces.


Usually, Net force = Applied force - various forces acting against you (gravity or friction etc.)
Hit the book, bro.

Answer 3

Applied force, natural force, friction, weight, tension, compression, bending, cohesion, adhesion, repulsion, attraction and you can find them all in the dictionary.

Answer 4

If you push something it moves. If you push it harder, it moves faster. If you push from opposite directions, nothing happens. That basically sums it up.