Lecture 11: Laws of motion. Newton’s 1 st Law: Inertia Matter resists motion If at rest, it will...
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Transcript of Lecture 11: Laws of motion. Newton’s 1 st Law: Inertia Matter resists motion If at rest, it will...
Newton’s 1Newton’s 1stst Law: Inertia Law: Inertia
Matter resists Matter resists motionmotion
If at rest, it will stay If at rest, it will stay at restat rest
If in motion, it will If in motion, it will stay in motionstay in motion
Mass is a Mass is a measure measure of of inertiainertia
Newton’s 2Newton’s 2ndnd Law Law
An unbalanced An unbalanced force acts on force acts on objects equal to objects equal to its its mass mass and and accelerationacceleration
F = m X aF = m X a
F = forceF = force m = massm = mass a = acceleration a = acceleration
GravityGravity
All objects in the All objects in the universe attract universe attract each othereach other
Gravity is a Gravity is a function of function of mass mass and and distancedistance
More mass= More mass= more more gravitygravity
More distance = More distance = less less gravity gravity
Weight and gravityWeight and gravity
The pull of gravity on The pull of gravity on Earth is 9.8m/s Earth is 9.8m/s 22
Weight is mass X the Weight is mass X the pull of gravity (w=mg)pull of gravity (w=mg)
Q: are weight and mass Q: are weight and mass the same?the same?
Q: do we weigh the Q: do we weigh the same on the moon as same on the moon as on earth?on earth?
Terminal velocityTerminal velocity
The maximum The maximum speed objects fall speed objects fall to earth isto earth is
200 mi/h or 200 mi/h or 320km/h320km/h
How does the How does the parachute slow the parachute slow the fall?fall?
Newton’s 3Newton’s 3rdrd Law Law
Forces act in pairsForces act in pairs
For every For every actionaction force, there is an force, there is an equalequal and and opposite opposite reactionreaction force force
Momentum = mass X velocityMomentum = mass X velocity
The greater the The greater the mass, the greater mass, the greater the momentum.the momentum.
Ex: semi trucks Ex: semi trucks take longer to stop take longer to stop than cars.than cars.
Q: will momentum Q: will momentum be greater at more be greater at more velocity?velocity?