Chapter 5 and 6: Motion
Terms
undefined, object
copy deck
- force
- a push or pull
- newton
- (N) unit of measurement for forces
- net force
- the combination of all the forces acting on an object
- balanced forces
- Forces whose net force is 0
- unbalanced forces
- forces whose net force is not equal to 0 and cause a chage in motion
- friction
- a force that oppses motion between 2 surfaces that are in contact
- Why does friction occur?
- Friction occurs b/c no surface is completely smooth. They all have grooves that get caught in those of the other surace when they move past each other, causing friction.
- Ways to increase friction
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-using an object with more mass, and therefore more weight (more downward force)
-pushing surface w/more force onto other (more downward force)
-make surfaces rougher - Ways to decrease friction
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-using an object w/smaller weight
-use smoother surface/smoothen surface
-lubricant
-switch from sliding to rolling friction - What are the types of friction
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kinetic friction - friction between moving surfaces
static friction - friction that balances and other forces on the object and keeps it not moving - Gravity
- the force of attraction between objects that is due to their masses
- types of kinetic friction
-
-sliding: results from 2 rough surfaces in motion
-rolling: a wheel in contact w/flat surface
-fluid: a gas or liquid opposing motion - Newton's Law of Universal Gravitation
- force of attraction btw ll objects depends on madd of objects and distance apart
- Forces involved with projectile motion
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-Gravity: causes object to accel. downward
-Air resist.: causes horizontal accel to decrease - Explain falling objects
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-accelerate due to gravity
-accel. decreases b/c of air resis. but sped keeps increasing but at slower rate until accel=0 and travels at a constant speed until hitting ground - Weight
- amount of gravitational force exerted on an object
- mass
- amount of matter in an object
- terminal velocity
- the constant velocity of an object in which the force of gravity is equal to the amount of air resis.
- free fall
- motion of a bosy when only force of gravity is acting on the body
- centripetal force
- unbalanced force that causes objects to move in a circular path
- projectile motion
- curved path an object follows when thrown or propelled near the Earth's surface
- Newton's 1st law
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-objects at rest will stay at rest
-objects in motion will stay in motion until acted on by an unbalanced force - inertia
- tendency of an object to resist a change in motion
- Newton's 2nd Law
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acceleration of an object depends on the mass of the object and amount of force applied
f=ma - Factors Affecting Terminal Velocity
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shape
weight
density of air
texture of object
think of skydivers - Newton's 3rd Law
- For every action, there is an equal and opposite reaction