8TH GRADE SCIENCE FINAL
Terms in this set (70)
A position or reference point
The location of an object
A location to which you compare other locations
A change in position over time
How is average speed calculated
By dividing the distance an object travels by the time it take to cover the distance.
Formula: Average Speed= Distance/Time
A speed in a specific direction
The rate at which velocity changes
How is average acceleration calculated
Average acceleration = (final velocity - starting velocity)/time
What is an example of positive acceleration
Sliding down a hill
What is an example of negative velocity
A race car slowing down
Acceleration in a circular motion
Moving at a steady rate over time
A push or a pull
the act of applying force in order to move something away
What is an example of a contact force
What is an example of a force acting from a distance
Gravity and Magnetic Force
The combination of all forces acting on an object
Newton's First Law of Motion
An object at rest stays at rest, and an object in motion stays in motion at the same speed and direction, unless it experiences an unbalanced force
What is an example of Newton's First Law of Motion
A gold ball on a tee; A chair
The tendency of an object to resist a change in motion
Newton's Second Law of Motion
The acceleration of an object depends on the mass of the object and the amount of force applied.
What is an example of Newton's Second Law of Motion
An empty shopping cart accelerating after a small force was applied. While a full shopping cart has a much smaller acceleration with the same force applied to it.
Newton's Third Law of Motion
Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.
What is an example of Newton's Third Law of Motion
If you push up against a wall, the wall is pushing back against you
A force of attraction between object due to their mass. It is a non-contact force that acts between two objects at any distance apart.
What is an example of gravity
When a skydiver is far from the ground, Earth's gravity still pulls him downward
Does Earth's gravity accelerate all objects in the same way
How do you calculate the force of gravity
By multiplying the mass of the object(m) by the factor due to gravity(g)
Formula: F= mg
the motion of a falling object when the only force acting on it is gravity
The path of an object as it revolves around another object in space
An upward force that fluids exert on all matter
How does an object float
An object will float if the object's weight is equal to the buoyant force.
How does an object sink
An object will sink if the object's weight is greater than the buoyant force.
How is density calculated
mass divided by volume
Is the use of force to move an object some distance in the direction of the force.
How is work calculated
Force times distance
Formula: W= FxD
the ability to do work
What is an example of energy
A dog pulling a sled
the rate at which work is done
How is power calculated
Energy divided by Time
Formula: P= E/T
the energy an object has due to its motion
How is kinetic energy calculated
Mass(m) times Speed(v) squared divided by two
What form of measurement is kinetic energy expressed in
the energy an object has because of its position, condition, or chemical composition
How is gravitational potential energy calculated
Mass times acceleration time height
the energy possessed by an object due to its motion and position
How is mechanical energy calculated
Kinetic Energy plus Potential Energy
Any device that helps people do work by changing the way work is done.
How many types of simple machines are there and what are they
They're 6 types; Levers, wheels and axels, pulleys, inclined planes, wedges, and screws
The number of times a machine multiples the input force.
How is mechanical advantage calculated
output force divided by input force
a comparison of a machine's work output with the work input
How is Mechanical Efficiency calculated
Work output divided by work input expressed as a percent
a simple machine that consists of a bar that pivots at a fixed point called a fulcrum
Ideal Mechanical Advantage
the mechanical advantage of a machine that is 100% efficient
How is ideal mechanical advantage calculated
ideal mechanical advantage = input distance/output distance
first class lever
The fulcrum is between the input force and the load. They change the direction of the input force.
second class lever
The load is between the fulcrum and the input force. They don't change the direction of the input force. They allowed you to apply less force than the load.
What is an example of a second class lever
wheelbarrow, bottle-cap openers, and staplers
third class lever
The input force it's between the fulcrum and the load. They do not change the direction of the input force.
What is an example of a third class lever
Hammers and baseball bats
wheel and axle
a simple machine made of a wheel connected to a smaller cylindrical object, the axle.
What are some examples of a wheel and axle
doorknobs, tires and screwdrivers
a simple machine that has a grooved wheel that holds a rope or a cable.
attached to something that doesn't move. These pulleys do not change the size of the force.
it is attached to the object being moved. These pulleys do not change the direction of the force, but does increase the force
block an tackle pulley
A pulley system made by combining a fixed pulley and a movable pulley. These pulleys change the direction of the force and increase the force
a straight, slanted surface used to raise an object
A pair of inclined planes that move. There is one thick end and one thin end. They are used to cut and split object's.
An inclined plane wrapped in a spiral around a cylinder.