Flashcards in Force, Newton's Laws and Energy Test Deck (51):
A push or pull
The combination of all forces acting on an object
The units for force
The units for energy
What type of forces lead to acceleration?
Can an object move if forces are balanced?
YES! If forces are balanced an object it moves at a constant velocity. If you are pedaling your bike at a constant velocity, you are still exerting force but friction is matching you.
What is the general rule for the direction of friction?
Opposite the direction an object is moving
The force that opposes motion
What force exists when an object is being pushed or pulled but not moving?
This friction occurs when a solid moves through a liquid or a gas
Air resistance is an example of
Skateboards or wheels experiences
What force pulls objects towards each other?
What two properties affect the strength of gravity?
Distance between the objects and Mass
Objects that are close together
exert a strong gravitational pull
Objects that are massive
exert a strong gravitational pull
A resistance to a change in motion (related to 1st law) Objects with lots of inertia resist a change in motion. Objects with lots of mass have lots of inertia.
Objects in motion stat in motion unless acted upon by an outside force.
Mass, force and acceleration are related: F = MxA
It takes a large force to accelerate a large mass or cause a large acceleration
Every action has an equal an opposite reaction.
WHICH LAW? A soccer ball sits in a field?
1st... it stays at rest
WHICH LAW? A soccer ball rolls to a stop.
1st... it stays in motion until friction acts on it
WHICH LAW? When kicked a canon ball accelerates less than a soccer ball
2nd... the large mass of the cannon ball is hard to accelerate
1st... the motion of the canon ball is hard to change because of its large inertia.
WHICH LAW? SUVs use more gasoline to accelerate at 10 mi/hr/s than do motorcycles
2nd... the large mass of an SUV require more force (gas) to accelerate at the same rate as a less massive vehicle
WHICH LAW? A swimmer pushes water backwards with her feet to move forwards
3rd... the water pushes on the swimmer just as hard as she pushes on the water
WHICH LAW? The Sun and the Earth exert the same gravitational force upon each other.
3rd... All force pairs are equal and opposite. However, the Earth accelerates more from the same sized force because it has far less mass.
WHICH LAW? The harder you hit a volleyball, the more it hurts
3rd... The volley ball exerts more force on your hand as you put more force into it.
The energy of motion
KE depends on
Mass and velocity
Gravitational Potential Energy
Energy stored in objects with mass and height and also experiencing gravity.
Elastic Potential Energy
Energy stored in something that is stretched or compressed
Energy associated with fields of force around charged particles
Energy related to vibrating atoms or molecules... vast vibrations is high energy
Chemical Potential Energy
Energy stored in the bonds between atoms. When these bonds are broken it makes the atoms shake, increasing thermal energy
WHAT TYPE OF ENERGY? Light
WHAT TYPE OF ENERGY? Radio Waves
WHAT TYPE OF ENERGY? X rays
WHAT TYPE OF ENERGY? A car moves across flat ground
WHAT TYPE OF ENERGY? A hammer waits to fall
WHAT TYPE OF ENERGY? The atoms in an iron pan vibrate and cook meat
WHAT TYPE OF ENERGY? A log waits to burn in a fireplace
WHAT TYPE OF ENERGY? A candy bar
WHAT TYPE OF ENERGY? A bungie cord is stretched and waiting to pull a person back up.
WHAT TYPE OF ENERGY? A Slinky waits at the top of the stairs
WHAT TYPE OF ENERGY? A slinky is stretched across the floor of a science classroom.
WHAT TYPE OF ENERGY? someone runs
Energy cannot be...
created nor destroyed... only changed from one form to another.
Energy appeared to be lost in the marble roller coaster because...
we did not keep track of heat energy. Friction turned KE into thermal energy.
When was KE high on the marble roller coaster?
when the hight was low... this allowed for GPE to be converted into large velocities or large KE.