All objects fall with the same acceleration.
This acceleration is due to gravity.
Objects fall to the ground at the same rate because the acceleration due
to gravity is the same for all objects. Any
differences in force are canceled by the differences in mass.
All objects accelerate toward the earth at a rate of 9.8 m/s/s.
This is known as the gravitational constant.
This means that for every second an object falls, the objects downward
velocity increases by 9.8 m/s/s. The
velocity of a falling object can be calculated using the formula,
ΔV = g (9.8) x T
A)
AIR RESISTANCE
Air resistance slows down acceleration. Air resistance is a form of fluid friction. Fluid friction opposes the motion of objects moving through the air. Air resistance occurs between the surface of the object and the air that surrounds it. The amount of air resistance acting on an object depends on the size and shape of the object. To find the net force of a falling object, subtract the force of air resistance from the force of gravity.
Acceleration
stops at terminal velocity. As an
object falls, the upward force of air resistance continues to increase until it
exactly matches the downward force of gravity.
When this happens, the net force equals zero and the object stops
accelerating. The object then
continues to fall at a constant velocity, called the terminal velocity.
Free
fall occurs when there is no air resistance.
An object is in free fall only if gravity is pulling it downward and no
other forces are acting on it. Free
fall only occurs in a vacuum (no air). Orbiting
objects are in free fall.
Two
motions combine to cause orbiting. An
object is said to be in orbit when it is traveling in a circular or nearly
circular path around another object. The
unbalanced force that causes objects to move in a circular path is called
centripetal force.
Projectile
motion is the curved path an object follows when thrown or propelled near the
surface of the Earth. Two motions
combine to form projectile motion;
1) Horizontal motion – Motion that is parallel to the
ground.
2) Vertical motion –
Motion that is perpendicular to the ground.
The vertical motion
is caused by gravity pulling downward on the propelled object.
Newton’s
First Law of motion:
An object at rest remains at rest, and an object in
motion remains in motion, at a constant speed and in a straight line, unless
acted on by an outside force. Because
of friction, it is difficult to observe the effect of Newton’s first
law on the motion of everyday objects.
Also
known as the ‘Law of Inertia’
Objects with small masses have less inertia than
objects with large masses.
Newton’s Second Law of motion:
The acceleration of an object depends on the mass of
the object and the amount of force applied.
Also known as the ‘Law of Acceleration’
1)
Acceleration depends on mass, as mass increases acceleration decreases.
The opposite is true also.
2)
Acceleration depends on force. Acceleration
increases as force increases. The
opposite is true also.
3)
Newton’s second law can be calculated using the formula, A=F/m.
Newton’s Third Law of Motion:
Whenever one object exerts a force on a second object, the second object
exerts and equal and opposite force on the first object.
All forces act in pairs.
Also known as the ‘Law of Action/reaction’
For every action, there is an equal and opposite reaction.
The Law of Conservation of Momentum:
Momentum is a property of moving objects that depends on the object’s
mass and velocity. The more
momentum an object has, the harder it is to stop or change direction.
Any time two or more objects interact, they may exchange momentum, but
the total amount of momentum stays the same.