Download STC Lessons 2-6 – Study Guide Energy transformations (Especially

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STC Lessons 2-6 – Study Guide
Energy transformations
(Especially the battery you made to
light up a light bulb)
Chemical ElectricalLightHeat
Types of Energy
Kinetic
(See handout)
Defn:
Types of Energy
Potential
(See handout)
Defn:
Battery---Wires----Light Bulb
energy of motion or movement
(see handout for specific energy types)
energy that is stored; of position or gravitational
(see handout for specific energy types)
Definitions:
force
-a push or a pull
gravity
-the force of attraction between all matter
elastic force
-the force exerted by elastic materials such as rubber bands
and springs
spring scale
-a calibrated spring used to measure force (newtons)
weight
-the measure of the fore of gravity on an object
mass
-the measure of the amount of matter in a body
newton
-unit of force in the metric system
inertia
-the resistance of an object to a change in the speed or the
direction of its motion
balance scale
-an instrument used to find the weight or mass of an object by
balancing other objects with the same mass (triple beam
balance scale)
-objects at rest remain at rest, and objects in motion remain in
motion with the same velocity, unless acted upon by an
unbalanced force
Newton’s 1st Law
Balanced vs. Unbalanced forces
Balanced Forces –the motion does not change; the net force
on an object is zero, the forces acting on the object are
balanced (same effect as no force).
Unbalanced Forces- change the motion of an object or is
pushed or pulled with greater force
“Bungee Jumping: The Forces are with
You” EMMp.42-44
(Related forces involved in bungee
jumping.)
Gravity pulls you down; the Elastic Forces respond-elastic is
pulled and stretched a great distance so a stronger force pulls
you up, overcoming gravity. You rise and then it repeats with a
little less movement each time.
Inquiry
Conclusions:
Ls. 5
elastic force
Hooke’s Law
Ls. 6 friction force and how it is
affected by the following
surface type
-In our experiments, we increased the stretch of a rubber band
(independent variables) measured by a spring scale (force in
newton’s) to find the (dependent variable). The force
increased each time we stretched the rubber band further.
-States that the force a spring exerts depends on how far it is
stretched.
Frictional force increases when the surface is rough. Fine
sandpaper had more friction than the coarse sandpaper. Wax
paper, paper towel, and tabletop had less.
weight (load)
More weight increased frictional force (more pressure on
surface)
surface area
Surface area of an object did not increase frictional force.
Factors that determine the amount of
friction between two surfaces.
Pressure (weight) and surface type
Types of friction:
Rolling
When one surface/object rolls over another surface/object
without sliding. Ex. Wheels and ball bearings decrease friction.
Sliding
When two surfaces rub or slide across each other
(To reduce friction, an oil or lubricant is used-especially in
machinery.)
Static
Two surfaces/objects touching but not moving. Standing still
(pressure between objects)
Fluid
(wind resistance, air resistance, drag)
One of the two surfaces/objects comes in contact with a fluid
(like air or water) and pushes on the surface/object.
“Nature Puts on the Brakes.” EMM p.54-58
(air resistance, forces in skydiving)
Forces involved are gravity (pulling down) and air resistance/air
friction/drag/fluid friction (pushes up).