J White – 6wks exam review

Question Answer
Energy is the ability to cause __________. Change
When something is able to change in its enviroment or itself, it has _________. Energy
Energy in the form of motion Kinetic Energy
Kinetic Energy depends on two quantities Mass and velocity
The formula for Kinetic Energy is KE = 1/2mass X velocity^2 (velocity is squared)
The SI unit of energy Joule
Motionless objects that have energy have ___________ Potential energy
Potential energy is the energy of _________. Position
Energy stored by things that stretch or compress Elastic Potential Energy
Energy stored in chemical bonds between atoms Chemical Potential energy
Energy stored by things found above the Earth's surface Gravitational Potential Energy
The amount of GPE in an object depends on mass, acceleration due to gravity and heith above the ground.
What number is the acceleration in the GPE equation? 9.8 m/s^2
The unit for mass kilograms
The unit for height meters
You have two objects. One is 3 feet above the ground and the other is 6 feet above the ground. Which object will have MORE GPE? The second object. Why???
Two objects are on a shelf at the same height. The first object has a mass of 5 kg and the second object has a mass of 10kg. Which object has a lower GPE? The first object. Why???
As an object falls from a shelf, the ________energy is decreasing and its __________is increasing. potential, kinetic
An example of an object with electrical energy would be a ____________. Light bulb.
The warmth you feel from a light bulb is __________. Thermal energy.
When a car uses gasoline, the fuel is stored in the form of _________. chemical potential energy
The engine transfers the energy in the gasoline from ___________ to ___________. chemical potential energy to kinetic energy
Energy is converted between potential and kinetic energy. The total amount of energy in a system is ____________. Mechanical energy
The formula for Mechanical Energy is _________- ME = KE + PE
The mechanical energy is due to the __________and _________ of an object. position and motion
When a baseball is hit will it have high KE or low KE? Will it have high GPE or low GPE? high KE, low GPE
After the ball is hit, it soon begins to fall. As the ball is falling will it have high or low GPE? High or low KE? low GPE, high KE
While you are on a swing, at the highest point, your energy will be in the form of _________ potential energy, KE = 0
As you begin to fall towards the earth, your energy is in the form of ___________ Kinetic Energy
Energy can not be created or destroyed Law of Conservation of Energy
When you are blow drying you hair, the law of conservation of energy is in effect. The Energy going in to the hair dryer is ____________. Electrical Energy
When you blowdry you hair, the energy going out of the hair dryer is _____________________ Thermal, Kinetic, and sound energy
When you are on a swing, what slows you down? friction ( from the ropes or chains) and air resistance
Nuclear Fusion Mass is converted into energy. In Nuclear Fusion, nuclei are fused together. ( How the sun heats and and gives light to the Earth)
Nuclear Fission Nuclei do not fuse. they are broken apart. Heat is released.
Where do we find evidence of Nuclear Fission? Nuclear Power Plants. Generation of Energy
Energy in food Chemical Potential Energy. When you digest food, the molecules break down and the energy in the chemical bonds is released.
Calorie Used to measure how much energy you get from various foods. 1 Calorie is equivalent to 4,180 Joules.
Green plants store energy in the form of __________ energy Light
Friction causes some of the object's mechanical energy to be converted to _________ energy Thermal energy.
If you don't SEE something move, is it possible that motion took place? Yes. For example, when you look outside and see a mailman at your mailbox and then notice later that he is 5 houses down. You did not see the truck move but it did.
What are the the requirements to have motion? distance and time
What helps you determine if something has moved or not? A refernce point
What is the SI Unit for distance? meter (m) or kilometer (km)
What is distance? How far an object has moved
What is displacement? the distance and direction of an object's change in position from the starting point.
What is speed? The distance and object travels per unit of time.
What is rate? Any change over time.
Formula for speed – S = d/t ( distance divided by time)
Units for speed – m/s or km/min
What is the formula for GPE? GPE = mass X 9.8 m/s^2 X height
When you are graphing speed, what will be the x axis? y axis? x = time y = distance
What is average speed? the total distance traveled divided by the total time.
What does a speedometer tell you? Instantaneous speed
What is instantaneous speed? the speed at any given point in time.
On a distance-time graph, you see that there is a horizontal line for abour 20 minutes. What does this mean? zero speed ( if someone rested for 20 minutes)
Velocity? Speed and Direction of an object. Example: 3m/s north
Motion of the Earth's Crust: So gradual that you don't even notice its movement.
What kind of acceleration will you have when a car is speeding up? slowing down? speeding up – positive acceleration; slowing down – negative acceleration
What is acceleration? The change in velocity ( m/s) over time (s) A = vf-vi / t Acceleration is equal to the intial velocity subtracted from the final velocity in an amount of time in seconds
6m/s^2 positive acceleration at a rate of 6 meters per second per second
-6 m/s^2 negative acceleration at a rate of 6 m/s/s
What is force? Force is a push or pull that one body exerts on another.
What happens to the motion of an object when you exert a force on it? A force can cause an object to change.
Balanced forces Action on ONE object… 2 equal size forces but in opposite directions. EX: 2 students pushing on a box and the box does not move
Net Force? When two or more forces act on an object at teh same time, the forces are combined. If the net force is zero, the forces are balanced.
Unbalanced forces unequal forces. example: two students push a box, and they are both standing on the left side of the box. the forces may be equal in size BUT ARE NOT OPPOSITE IN DIRECTION.
Inertia? the tendency of an object to resist change in its motion. If an object is moving, it will continue moving in that direction until an unbalanced force acts on it.
Newton's First Law of Motion An object moving at a constant velocity ( or speed) will continue to move at that velocit unless a force acts on it.
What will increasing the mass of an object do to its inertia? Increase the mass increase the inertia
Is m/s a correct unit for acceleration? NO. m/s is the unti for velocity.
When a passenger does NOT wear a seatbelt in the car The passenger will hit the windshield due to the inertia of the person NOT wearing a seat belt.
DO I need to memorize the formula for KE ( kinetic energy) and for GPE ( gravitational potential energy GPE) ? Yes
What is the formula for Acceleration? A = F/M (acceleration equals force divided by mass)
What the units for Force? Newtons
What is the formula to solve for Force? F = M X A ( mass times acceleration)
The acceleration of an object depends on what two things? mass and force
What are the units for mass? grams or kilograms
Newton's second law of motion the net force acting on an object causes the object to accelerate in teh direction of the net force. Acceleration is determined by the mass of the object and the size ( in Newtons) of the force.
Friction? Friction is the force that OPPOSES motion between two surfaces that are touching each other. ( example: Why a skateboard gradally slows to a stop)
Static Friction The friction between two objects that are NOT moving past each other.
Sliding Friction is the force that opposes the motion of two surfaces sliding past each other. Adding more force will help overcome the sliding force ( example: when you are pushing a box – more force ( when you have someone help you push) overcomes sliding friction
Rolling Friction What makes a train's wheels turn on tracks or a car's wheels turn on the road
Air resistance reacts in the opposite direction of the falling object. This is why a piece of paper floats to the ground slower that a wadded up paperball, when they are dropped at the same time.
Weight The gravitational force exerted on an object. Weight = mass X 9.8 m/s^2 ; Another word for Weight is gravitational force.
Newton's Third Law to every action force their is an equal and opposite reaction force. Action-reaction Pairs.
centripetal force an unbalanced force acting on an object in the direction towards the center.
centripetal acceleration acceleration towards the center of a curved or circular path.
Momentum How much force is needed to change an objects motion
Momentum formula Momentum ( p) = mass X velocity
What does "p" stand for? Momentum
Do I need to know the formula for force and momentum? Yes!
If you are standing at the top of a hill and someone shoves you, what kind of acceleration will you have as you roll down the hill? positive
What is the best thing you should use to study? The Ch 2,3,4 Notetaking worksheets
Do I need to know the differences concerning Newton's Laws? YES! You need to know what they mean and what formulas are associated with them.
Should I check out a book after school on Monday? Yes, you can if you feel you need to!
When is the 6 weeks exam? Tuesday, February 8th
Projectile Motion When you toss a ball ( which is called a projectile) you have noticed that a ball does not travel in a straight line. The ball tends to curve downward.
Projectile Anything thrown or shot into the air.
Projectile path Because of Earth's gravitational pull and their own inertia, projectiles follow a curved path.
Example of centripetal force when a car rounds a sharp curve ona highway, the centripetal force is the friction between the tires and the road surface.