Terminal Velocity

a) Calculate the resultant force

b) State if the object is accelerating or not and in which direction

• a) 50N

  b) accelerating to the right

• a) 50N

  b) not accelerating

• a) 50N

  b) accelerating downwards

• a) 0N

  b) not accelerating

a) Calculate the resultant force

b) State if the body is accelerating or not and in which direction:

• a)0.5N

  b) accelerating downwards

• a) 0.5N

  b) accelerating upwards

• a) 0N

  b) not accelerating

• a) 0.5N

  b) not accelerating

a) Calculate the resultant force of each diagram.

b) State if the body is accelerating or not and in which direction

• a) 1.5N

  b) accelerating upwards

• a) 1.5N

  b) accelerating downwards

• a) 15N

  b) accelerating downwards

• a) 15N

  b) not accelerating

John, of 68kg dives out of an aeroplane

a) What is John's weight

b) What happens to John's weight as he falls?

• a) 0.68N

  b) stays the same

• a) 680N

  b) stays the same

• a) 680N

  b) increases

• a) 0.68N

  b) decreases

A skydiver steps out of a plane. She falls and a) ______________. This is because the force b) ________________ (weight) is c) ________________ than the force upwards ( d) _______ _______________

When a skydiver is falling what happens to

a) her velocity

b) the air resistance?

• a) Increases

  b) increases

• a) increases

  b) decreases

• a) increases

  b) stays the same

• a) stays the same

  b) increases

Explain why the skydiver will eventually stop accelerating

• The air resistance continues to increase as long as the velocity increases. When the air resistance reaches the same value as the weight there will be no resultant force, hence no acceleration (F=ma)

• The air resistance continues to decrease as long as the velocity increases. When the air resistance is larger than the weight there will be no resultant force, hence no acceleration (F=ma)

• The air resistance stays the same so the velocity increases. There will be no resultant force, hence no acceleration (F=ma)

• The air resistance continues to increase as long as the velocity increases. When the air resistance reaches the same value as the weight there will be an increase in acceleration

a) When should a sky diver open his/her parachute?

b) Why?

• a) anytime

  b) a parachute has a large surface area so increases air resistance

• a) Anytime

  b) Since this will be when the air resistance is at a maximum. This will give the greatest increase in drag needed to slow down the diver.

• a) When the resultant force is zero (air resistance = weight)

  b) a parachute has a large surface area so increases air resistance

• a) When the resultant force is zero (air resistance = weight)

  b) Since this will be when the air resistance is at a maximum. This will give the greatest increase in drag needed to slow down the diver.

Choose from the words in the diagram to fill in the blanks:

When a skydiver jumps out of a plane, his weight is _________________ than his air resistance, so he _________________ downwards. This causes his air resistance to _________________ until it _________________ his weight. At this point his velocity is _________________. When his parachute opens, his air resistance is _________________ than his weight, so he _________________. This causes his air resistance to _________________ until it _________________ his weight. Then his velocity is _________________ once again