Types of forces lesson 2

lesson 2

by Nipuni Marasinghe

Weight or gravitational force

Frictional Force

Upthrust

Multiple Choice

Can you make a guess what this is?

• a porcupine

• a sea urchin

• iron powder with a magnet underneath

Magnetic Force

Magnetic poles

• Like poles attract

• Unlike poles repel

Multiple Select

Select all the applications of magnetic force

• in Door and window locks

• in scrap yard cranes

• in speakers

• in light bulbs

• in motors

Multiple Choice

Is magnetism a contact force?

• Yes

• No

Surface Tension

Multiple Choice

Do you think surface tension is a contact force?

• Yes

• No

• Water strider

Multiple Select

Which of the experiments below do you think relate to surface tension?

Investigation on surface tension

Air resistance or Drag force

• a force created when air particle knock against a moving object

• Acts in the opposite direction of movement of the object

• air particles bounce and knock on the windscreen

• 
  

Multiple Select

Which of these statements are true about air resistance force?

• it speeds up a moving object

• slows down moving object

• is a contact force

• the force is produced when air particles knock against the surface of the moving object

Reducing air resistance

• Streamlined:The word 'streamlined' refers to something that is smooth and pointed at at least one end. Race cars, rockets, and jets are often streamlined because the shape makes them able to move more quickly.

Multiple Choice

Which of the following cars model designs fits to have the least amount of air resistance?

• Spoilers to reduce the drag force

• Aerodynamics

• 
  

• 
  

Water Resistance

Contact force

Similar to air resistance

Using water resistance

Flowriderand water slides

Multiple Select

Which statements are true about water resistance?

• slows moving objects in water

• pointed body can reduced water resistance

• happens only on the surface of water

• is a non contact force

Reducing air resistance

Multiple Choice

Swimmers consider a great deal in reducing water resistance. Which one of the swim wear do you think is permitted in Olympics rules?