Download Motion Forces and Work rvw pak 13.14

Motion, Forces, and Work
7.P.1 Understand motion, the effects of forces on motion and the graphical representations of
motion.
7.P.1.1 Explain how the motion of an object can be described by its position, direction of
motion, and speed with respect to some other object.
7.P.1.2 Explain the effects of balanced and unbalanced forces acting on an object (including
friction, gravity and magnets).
______________________________________________________________________________
The object that appears to stay in place is the _________________.
Motion –
Speed –
Most of the time objects do not travel at a constant speed so you calculate average speed.
Average speed = total distance / total time
Velocity –
Speed and velocity are not the same!! ___________ includes a reference direction.
Finding resultant velocities:
When you combine two velocities in the same
direction, _________________________.
When you combine two velocities that are in
opposite directions, ____________ the
smaller velocity from the larger velocity. The
resultant velocity is in the direction of the
larger velocity.
Acceleration –
.. . .
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Positive acceleration –
Deceleration (negative acceleration) –
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Force –
15 m/s east + 1 m/s east = 16 m/s east
15 m/s east – 1 m/s west = 14 m/s east
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. . ..
More than one force is acting on an object. The _______________ is the combination of all the
forces acting on an object.
Describe Balanced and Unbalanced Forces and give an example of each:
Balanced Forces
Unbalanced Forces
Sketch a distance vs time graph of motion with an unbalanced force acting on an object.
Sketch a distance vs time graph of motion with a balanced force acting on an object.
Friction –
Describe the Types of friction and give examples of each:
Kinetic friction
Static friction
Ways to reduce friction:
Ways to increase friction:
Gravity –
All matter has _______. Weight is a result of _______ pulling on an object. All matter is affected
by gravity.
Weight –
Mass –
Newton’s Laws of Motion
1st Law
2nd Law
3rd Law
Inertia –
Momentum –
7.P.2 Understand forms of energy, energy transfer and transformation and conservation in
mechanical systems.
7.P.2.1 Explain how kinetic and potential energy contribute to the mechanical energy of an
object.
7.P.2.2 Explain how energy can be transformed from one form to another (specifically potential
energy and kinetic energy) using a model or diagram of a moving object (roller coaster,
pendulum, or cars on ramps as examples).
7.P.2.3 Recognize that energy can be transferred from one system to another when two objects
push or pull on each other over a distance (work) and electrical circuits require a complete loop
through which an electrical current can pass.
7.P.2.4 Explain how simple machines such as inclined planes, pulleys, levers and wheel and
axels are used to create mechanical advantage and increase efficiency.
Work –
Work is done on an object if two things happen:
1.
2.
Describe a situation in which work is not being done.
The amount of work (W) done in moving an object can be calculated by multiplying the
___________ applied to the object by the _____________ through which the force is applied.
Use the following words to fill in the blanks below:
Machine – Work input – Work output – Mechanical advantage –
____________ Is used to lift the object.
____________is the push or pull given to make the machine move an object over a distance.
____________is the number of times the machine multiplies the effort force.
____________makes work easier by decreasing force or increasing distance.
When mechanical advantage is greater than 1 we can ____________________________.
When mechanical advantage is less than 1 we can ________________________.
Mechanical Efficiency –
Sketch each tool in the correct space and explain how it makes work easier, and what happens
to the force.
Examples:
Levers
Pulleys
Wheel and Axle
Inclined Plane
Wedge
Screw
A pendulum is shown below at various heights in its swing. Label the following on the diagram:
Maximum potential energy
Maximum kinetic energy
Explain what happens as the pendulum swings from side to side.
How can you increase the efficiency of a machine?
Describe the difference in AMA and IMA.
Draw a complete electrical circuit and describe the parts.
Describe the energy conversions that take place when lighting a bulb.
Label PE/KE energy conversions on the roller coaster.