Types of Forces

Going ahead!!

by: Nipuni Marasinghe

CONTACT and NON CONTACT FORCES!!

Weight or Gravitational Force

+ Weight is a force that acts downwards

+ It is a non contact force

+ Weight is a force caused due to the gravitational field strength

+ Weight can also change with the mass of the object

• Weight depends on the mass.

• When the mass increases, weight also increases.

• Weight increases with the strength of the gravitational force

• The gravity of some places is greater than of another.

• Earth's gravitational field strength is greater than the moon, thus you would weigh less in the moon than on Earth.

The point at which weight acts!!

Activity on ruler shift.

Activity on center of mass in irregular object

Multiple Select

The weight of an object depends on two things which are:.....

• mass of the object

• the volume of the object

• the gravitational field strength

• the height of the object from ground

Multiple Choice

In which planet or place would you weigh more?

• Moon

• Earth

• Mercury

• Jupiter

Multiple Choice

From which point of the object does weight act?

• From the side of the object

• from the top of the object

• From the center of mass in the object

• From the bottom of the object

FRICTIONAL FORCE

• This is a contact force

• Caused due to rubbing of two surface

Multiple Select

What are the things that friction force can do?

• Slow a moving object

• Make an object roll and slide

• Produce heat

• Trip an object and make it fall

• Wear away the surface or material

Is Friction a nuisance??

or is it important??

Multiple Select

Which of these activities are related to frictional force?

• writing on a paper with a pencil

• float in water

• climb up a cliff rock

• to run a 100m sprint

• to make a fire in the wild

Upthrust force in water

• A force that opposes weight of an object in water

• Enables the object to float if both weight and upthrust are equal

Multiple Select

What are the factors that can increase or decrease the upthrust acting on an object

• The shape of the object

• the volume of the object

• The density of the liquid(water)

• the colour of the object

Multiple Choice

What made the pilot whales to drag ashore and loose the upthrust force?

• the water became less salty near the shore

• the water became less dense near the shore

• the water becomes cooler near the shore

Multiple Select

Which of these are true about upthrust force?

• it acts downwards

• it acts upward

• seen in water

• is a non contact force

• depends on the volume of the object and density of water

Multiple Select

Select the contact forces from the list given below

• Gravity

• Upthrust

• Friction

• Magnetic force

• Air resistance