A force is a pull or a push of one thing on another.
It is a vector quantity.
Its S.I unit is newtons (N)
The effects of force are:
It can speed up or slow down moving objects.
It can change the shape of an object.
It can change the direction of a moving object.
It can make a stationary object move.
The seven types of forces are:
Gravitational force
Normal reaction force
Air resistance force
Upthrust force
Magnetic force
Electrostaitc force
Nuclear force
Gravitational force is the force on a body due to the pull of gravity.
It is also called weight and weight can be calculated by using this formula.Weight=mxg
Normal reaction force is the upward force on a body from the surface it is restingon.
The normal reaction force prevents the object from sitting into the surface it is resting on.
Air resistance is a force that opposes movement of objects through air.
Drag is a force that opposes motion of objects through fluids.
Upthrust force is an upward force on an object immersed in a fluid.
It is done to the difference in pressure at the top and at the bottom of the object.
Magnetic force is the force experienced when two magnets are brought close to each other.
Electrostatic force are the forces between charges. Like charges repel while unlike charges attract.
Nuclear force is the force holding the nucleus of an atom together.
Balanced forces are forces of the same size but act in the opposite directions in the same line of action.
Balanced forces are also said to be in equilibrium (meaning they are in balance).
Unbalanced forces are forces that will make an object to accelerate in the direction of the force.
Springs and wires will stretch when a force is attached on them. They will return to their original length when the force is removed so long as they are not stretched beyond a certain limit.
Hooke's Law states that extension is directly proportional to force provided the elastic limit is not exceded.
Elastic bands don't obey Hooke's Law when force is applied to them.
Friction is the force that opposes the motion of two objects sliding over each other.
Safe stopping distance is the thinking distance and braking distance.
Thinking distance is the distance travelled by a car before applying the brakes after seeing an obstacle.
Reaction time is the time taken before the driver applies the brakes after he has seen an obstacle.
Braking distance is the distance travelled by a vehicle after the brakes have been applied.
Momentum is a quantity possessed by an object in motion.
It's S.I unit is Kgm/s and it's a vector quantity.
momentum=massxvelocity
The principle of momentum states that: The total momentum before collision is equal to the total momentum after collision provided no external forces act on the objects.
Elastic collision is a collision in which momentum and kinetic energy of the colliding objects is conserved.
Inelastic collision is a collision in which momentum is conserved but K.E is not conserved.
Newton's First law states that: A body will continue with it's state of rest or uniform motion unless acted on by another force.
Newton's Second law states that: The rate of change of momentum is directly proportional to the force applied.
Newton's Third law states that: If body A applies a force on body B, body B will also apply an equal and opposite force on body A.
Moment is the turning effect of a force.
Moment=FXd
Principle of moments states that: At equilibrium the sum of clockwise moments is equal to the sum of anticlockwise moments.