forces

• What direction does upthrust go

  up
• what direction does thrust go

  left
• what direction does friction(drag) go

  right
• What direction does weight go

  down
• When a force is applied to an elastic object, it can change shape.

  This is known as:

  deformation
• The object can be squashed =

  compression
• The object can be stretched

  tension
• What is a moment?

  The turning effect that a force produces about a pivot.
• What happens in Hooke's law

  The spring expansion keeps increasing by similar amounts until it is stretched to its maximum then it levels out
• What is the equation for calculating moments?

  moment (Nm) = Force (N) x distance (m)
• Calculate the moment of a person

  opening 2 m wide door with a force of 100 N.

  100 x 2 = 200 Nm
• What is force measured in

  Newtons (N)
• Describe the friction force:

  Is the force between surfaces. It increases with the

  roughness of a surface.
• Friction usually transfers energy to___

  thermal energy
• Which types of objects experience lower friction?


  smooth and those with small surface areas
• What force to objects experience when they move

  through a liquid or gas?

  drag
• Why are dolphins this shape?

  They are streamlined to reduce

  drag.
• Pressure is a measure of how a force is spread over an

  area. Write the equation and triangle to show how

  pressure is calculated:

  pressure = force

  area

  P = F/A
• A student balances on a giant

  dice. The sides of the dice are

  2 m long, and the total force of the

  student and dice is 600 N. What is the surface area of one side

  of the dice?

  2 m x 2 m = 4 m2
• A student balances on a giant

  dice. The sides of the dice are

  2 m long, and the total force of the

  student and dice is 600 N.What is the pressure on the floor

  under the dice.

  600/4 = 150 N/m2
• What are the two different units units for pressure?

  Pascals (Pa) and Newtons per square meter (N/m2)
• Describe and explain the change in

  atmospheric pressure as a

  hot air balloon rises into the sky.

  The atmospheric pressure decreases

  as you move up through the atmosphere.

  This is because the number of air molecules

  decreases and the weight of the air decreases
• Why does a deep-sea diver experience

  greater pressure than a swimmer

  who is swimming just below the

  surface?

  The pressure increases at greater depths, because

  there is a greater weight of water above you the

  deeper you go.
• Show the direction

  pressure is exerted

  by water in this beaker:

  pressure is exerted in all

  directions.
• A polystyrene cup floats

  on the surface of a pond.

  why is this

  upthrust and weight are equal

  (so it floats)
• A ships anchor sinks in

  the sea.Why is this

  weight force is greater than

  upthrust force (it sinks)