Physics Final! (Exam 2) Flashcards
Work
Force X Distance
Power
Work/Time
Energy
Ability to do work
Kinetic Energy
Energy of motion
Potential Energy
Stored energy
Thermal Energy
Amount of heat energy an object possesses. Based on mass and composition
Lever
A rigid bar resting on a pivot
Pulley
A wheel with a grooved rim around which a cord passes
Inclined Plane
A surface raised to the horizon, or forming with a horizontal plane any angle but a right angle
Wedge
A piece of hard material with with two principal faces meeting in a sharply acute angle for raising, holding, or splitting objects
Wheel and Axle
Simple machine consisting of a large disc wrapped around a smaller rod
Screw
A simple machine consisting of an inclined plane wrapped around a rod
Law of Conservation of Energy
Energy cannot be created nor destroyed, but transformed
Specific Heat
Smount of energy needed to raise 1 g of a substance 1oC
Mechanical Advantage
Number of times that effort force is multiplied
Efficiency
How input is turned into output
Conductors
A material that allows heat to flow through easily
Insulators
A material that does NOT allow heat energy to pass through easily
Heat
Measure of total kinetic energy of a system
Temperature
Average kinetic energy of a system
Jill does twice as much work as Jack does in half the time. Jill’s power output is:
Four times Jack’s power output
A heavy rock and a light rock are dropped from the same height and experience no significant air resistance as they fall. Which of the following statements about these rocks are correct?
When they reach the ground, the heavier rock has more kinetic energy than the lighter rock
Two cyclists who weight the same and have identical bicycles ride us the same mountain, both starting at the same time. Joe rides straight up the mountain, and Bob rides up the longer road that has a lower grade. Joe gets to the top before Bob. Ignoring friction and wind resistance, which one of the following statements are true?
The amount of work done by Joe is equal to the amount of work done by Bob, but the average power exerted by Joe is greater than that of Bob
Energy has the same units as:
Work
The unit for power is:
Watt
The unit of measure for mechanical advantage is:
There is no unit
What factor determines gravitational potential energy?
Mass
A block of wood is resting on a table. For work to be done on the block:
The block must move become of a force acting on it
Which machine is part of the lever family?
Pulley
An object gains a certain amount of potential energy when it is raised to a height of 10 meters. If it is now raised to a height of 20 meters, its potential energy is:
Doubled
The transfer of energy to a body by the application of a force that causes the body to move in the direction of the force is called:
Work
______ is defined as the rate at which work is done
Power
Which of the following processes requires the most work?
A person lifts 10 kg off the floor 1 m
The amount of work being done on an object can be increased by:
Increasing the distance the object is moved
Power output can be increased by:
Decreasing the amount of time the work is done
As a penny falls from the rest towards the ground,_______ energy is converted to______ energy
Potential, kinetic
Which has the greatest amount of potential energy?
A person on the 20th floor of a building
Maddie is studying physics and wonders what type of energy represents the sum of the KE and PE that a moving object has. Can you help her?
Mechanical
Hot objects begin to cool as:
Thermal energy in the object is transferred to the surrounding air
Insulation is used in the walls of buildings to:
Keep thermal energy from moving through the walls
When a popsicle melts, the particles:
Gain energy and move faster
Why does hot air rise?
Because the particles have more energy there is more space between them and are less dense
What type of material makes the best conductor?
Metal
What type of material makes the best insulator?
Styrofoam
Which is NOT a temperature scale?
Spring Scale
When an object is cooled, its molecules slow down and move closer together, causing the object to:
Shrink or contract
Temperature and heat have a _____ relationship
Direct
Thermal energy moves from ____ to ______
Hot, cold
An ice cube feels cold in your hand because:
Heat moves from your hand to the cube
What materials tend to have a high specific heat?
Insulators
Water is a good thermal:
Insulators
Essay: Name the three types of potential energy. Describe them and give an everyday example of each.
1: Gravitational Potential Energy: Description: This is the energy something has because of its position above the ground.
Example: Imagine holding a ball up in the air. The higher you lift the ball, the more potential energy it has. This energy can turn into kinetic energy when you drop the ball and it starts moving
2: Elastic Potential Energy: Description: This is the energy stored in stretchy or springy materials when they are stretched or compressed.
Example: Pulling back on a rubber band stretches it and stores elastic potential energy. When you release one end of the rubber band, it snaps back into shape, releasing the stored energy.
3: Chemical Potential Energy:Description: This is the energy stored in the bonds of chemicals and can be released during chemical reactions.
Example: Food contains chemical potential energy. When you eat food, your body breaks down the food molecules through digestion, releasing energy that your body uses to move, play, and stay active.
Essay: If a tree falls in the woods…and no one is there to hear it…does it make a sound? Give support for your answer.
Essay: Consider the following statement: “Simple machines make work easier.” Do you agree? Or disagree? Explain your reasoning.
Essay: Choose a compound machine of at least 3 simple machines. What are the simple machines present and how are they involved?
