gravity, weight, mass, falling objects, and centripetal force
DESCRIPTION
Any 2 masses exert an attractive force on each other. Force of gravity increases with mass and decreases with distance.TRANSCRIPT
Gravity, Weight, Mass, Falling Objects, and Centripetal Force
Law of Gravitation
Law of GravitationAny 2 masses exert an attractive
force on each other.Force of gravity increases with
mass and decreases with distance.
Weight vs. Mass
Weight vs. MassWeight is the gravitational force
exerted on an object by the Earth.Weight is a force, and mass is a
measure of the amount of matter an object contains.
Your mass is the same no matter where in the universe you are, but your weight will vary because of gravity.
Calculating WeightWeight is your mass multiplied by
the acceleration due to gravity (g) or 9.8 m/s2.
The formula for weight is:weight = mass x g
Where g = 9.8 m/s2
Weight and Mass
Celestial BodyGravitation
Factor Relative to Earth
Sun 27.9Mercury 0.38
Venus 0.91Earth 1Moon 0.17Mars 0.38
Jupiter 2.54Saturn 1.08Uranus 0.91
Neptune 1.19Pluto 0.06
Falling Objects
Air Resistance• The air resistance of an object
depends on its size, shape, and speed.• Air resistance and NOT the mass of an
object is why certain things fall more quickly than others.
• In a vacuum, there is NO air resistance, so all things fall at the same rate.
In a Vacuum
Exit Ticket
1. Why do you feel the force of attraction between you and the Earth, but not between you and your pencil?
2. What is the difference between weight and mass?
3. What is a vacuum and how do objects fall differently in a vacuum?
Projectile MotionThe path that an object takes when it
is thrown or shot through the air.This path is due to Earth’s
gravitational pull and the object’s own inertia.
Projectile Motion
Terminal VelocityAs an object falls, it accelerates and
its speed increases as does the force of air resistance.
The force of air resistance increases until it cancels out the force of gravity.
When the forces are balanced, the object no longer accelerates, so it reaches a constant speed called its terminal velocity.
Centripetal Force and g’s
Centripetal ForceCentripetal force is an unbalanced
force pushing or pulling an object towards the center of a circle.
Centripetal acceleration is acceleration towards the center of a curved or circular path.
Centripetal Force examplesfrom physicsclassroom.com
As a car makes a turn, the force of friction acting
upon the turned wheels of the car provides centripetal force required for circular
motion.
As a bucket of water is tied to a string and spun in a circle, the tension force acting upon the bucket provides the centripetal
force required for circular motion.
As the moon orbits the Earth, the force of gravity
acting upon the moon provides the centripetal
force required for circular motion.
No centripetal force example from physicsclassroom.com
Without a centripetal force, an object in motion continues along a straight-line path.
With a centripetal force, an object in motion will be accelerated and change its direction.
Weightlessness