Forces and Work in Everyday Life

Audrey Poulton presents a lesson on forces and work for grade 9 physical science. The lesson covers the definition and examples of forces, the difference between mass and weight, and how to calculate weight. It also explains the concept of work in science, including how to calculate it using force and displacement. The lesson concludes with a summary of the key points discussed.

What is the main topic of today's lesson?

• Chemical Reactions

• Light and Sound

• Forces and Work

• Electricity and Magnetism

Which of the following is an example of a force in everyday life?

• The pull of gravity on an object

• The taste of food

• The color of a car

• The smell of flowers

What is the unit of force?

• Kilogram

• Meter

• Joule

• Newton

How is mass different from weight?

• Mass is a vector quantity, weight is scalar

• Mass is measured in Newtons, weight in kilograms

• Mass can be measured with a spring balance, weight with a scale

• Mass is the amount of matter, weight is the force of gravity on that matter

What is the SI unit of mass?

• Newton

• Kilogram

• Meter

• Joule

How do you calculate the weight of an object?

• Weight = mass - gravitational field strength

• Weight = mass + gravitational field strength

• Weight = mass / gravitational field strength

• Weight = mass x gravitational field strength

If a car has a mass of 2,000 kg, what is its weight on Earth?

• 2,000 Newtons

• 20,000 Newtons

• 200 Newtons

• 2 Newtons

What must occur for work to be done in the scientific sense?

• A force must be exerted in the opposite direction of motion

• A force must be exerted with no motion

• A force must be exerted and there must be motion in the direction of the force

• There must be motion without any force

What is the formula for calculating work?

• W = F - d

• W = F x d

• W = F / d

• W = F + d

An object is dragged 8 meters by a 100 Newton force. How much work is done?

• 800 Joules

• 8000 Joules

• 80 Joules

• 8 Joules