gravity the force not the movie. forces force (n) is any influence that can change the trajectory,...
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Gravity
The force not the movie
Forces• Force (N) is any influence that can change the
trajectory, speed or shape of a body.• Change in state of motion of a body• Distortion of a body
Forces
• A force is represented by a vector with both direction and magnitude
Forces applied…
• In the same direction as motion will cause an acceleration.
• In opposing direction to the motion will cause a decceleration of the object
• In perpendicular manner to the motion will cause a deviation of the object.
Forces
• If a force is applied– in the same direction as the motion of a body it
will accelerate
– in the opposite direction as the motion of a body it will decelerate
– Perpendicularly to the direction of motion of a body it will change trajectories
Forces
• An equilibrium of forces is achieved when the resulting force is equal to 0
• ***– Add forces in the same direction– Subtract forces in opposing direction
1. Weight vs. Mass
Definitions
MASS: measure of the quantity of matter in an object
WEIGHT: measure of the gravitational force acting on an object
Mass• Amount of matter an object has
• Measured in g or in kg
• Is measured by a balance
Weight• Pull that gravity exerts on
an object
• Measured in N
• Measured by a scale
• If the mass increases…
To recap:
• Mass and Weight are not the same
• Mass is the amount of matter• Weight is the gravitational pull on this matter
• Mass is measured in g or kg• Weight (being a force) is measured in N
• Mass and weight are proportional to one another
2. Calculating the gravitational Force
Fg = mg
Calculating the gravitational force
• Fg = mg– Where Fg = gravitational force or weight (N)
m = mass (kg)g = gravitational constant
• If an object has a mass of 30g what is its weight in Newtons on our planet?
• What if it was on Mars?
Astronomical Phenomenon
• Tides:– Gravitational effect of
the moon (and Sun) on the hydrosphere
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