• Living things can move by themselves.
• Non-living things cannot move by themselves.
• There should be a force to make them move.
• To drive a bicycle, we apply force with our feet to produce motion.
• Thus we can say that force is required in producing motion in the body. For example the box does not move although the push of the person tends to move it.Read More...
• A push or pull acting on an object is called force.
• Force make things move or make things change their motion.
Figure 1: (a) A weightlifter is lifting (pulling) the weight
(b) A soldier is firing bullet from a machine gun
• Two natural forces that affect most of the motion we are aware of are the force of gravity and electromagnetic forces.
• Gravity is one of the universal forces of nature. It is the force of attraction by which terrestrial bodies tend to fall towards the center of the earth.Read More...
EFFECTS OF FORCE
• We cannot see force, but we can see its effects. The effects that a force can have on objects are:
• Motion is a change of position.
• When a person throws a ball, he or she puts it in motion and the position of the ball changes.
• When a baseball player runs around the bases, his or her position changes.
• Even, the force applied by the baseball batsman, changes the direction of the ball that is bowled at him/her.
TYPES OF FORCES
• Forces are acting everywhere in the universe at all times.
• There are different types of forces.
Gravitational force (Gravity):
• Gravity or gravitational force is the force that attracts objects to the centre of the Earth.
• Gravity is a key force in the universe, and it is the force which brought our planet into existence.
• Gravity is one of the simplest forces, and it can be illustrated through the classic story of Sir Isaac Newton and his apple.Read More...
• Friction is a force that slows down moving things.
• Friction is what happens when any two things rub against each other.
• These can be solid things, like our two hands rubbing together, or our skis rubbing on the snow, or a hammer hitting a nail, or they can be gases, like friction with the air slowing down our car, or liquids, like friction with the water slowing down a boat.
• Friction happens when the rough edges of one object snag on the rough edges of another object, and some of the object’s energy has to be used to break off those rough edges so the objects can keep moving.
• And when we rub two soft things together, like our hands, sometimes they squish into each other and get in each other's way.
• But even completely smooth, hard things have some friction. This friction is the result of the molecules in both objects being attracted to each other.Read More...