Forces, such as _______ and ________ cause objects to move
pushing and pulling
What is the difference between contact forces and non contact forces?
Contact forces are when there is physical contact with an object, non contact forces do not need to have physical contact for an object to move
Give an example of a non- contact force
gravity
What are the three kinds of friction?
Sliding friction, rolling friction, and fluid friction
Give an example of sliding friction
Snowboarding
Give an example of rolling friction
Skateboarding
Give an example of fluid friction
Swimming
objects that move on the surface of water must be able to ______
float
The mass of an object divided by its volume is called what?
density
How can a steel ship float? Explain.
Steel ships are heavy but they are large. Density is mass/ volume. Steel ships have a large volume so their density decreases
What two forces does an object need to fly?
lift and thrust
Explain the difference in air pressure above and below the wing of a plane?
Air passes above and below the wings of the plane. The air below the wing moves slowly so the pressure is higher; This causes an upward force.
Why do airplanes have a streamlined shape?
The shape of the plane helps minimize air resistance
What produces carbon dioxide and other gases that pollute the air and water?
Fossil fuels
From the pie chart on page 108 which form of transport produces the most CO2 globally in a year?
Cars at 42 %
