WARM UP!

Which of the following describes a force?

• a pull only

• a push only

• a push or pull or both

• neither a push nor a pull

What is the unit of force in metric system?

• Calorie

• Joules

• Newtons

• Pounds

How do forces occur?

• in pairs

• in triplets

• by themselves

• as single quantity

When you move a chair across the floor, what force must your push be stronger than?

• friction

• magnetic

• normal

• tension

A 500-N lady sits on the floor. How much force the floor exerts on her?

• 50 N

• 250 N

• 500 N

• 1000 N