Newton's First Law of Motion

What is a force?

(a)  

Give an example of a contact force (check the second paragraph of the "Identifying Forces" section).

• Magnetism

• Gravity

• Air resistance

• A bird pushing a snake

What is the non-contact force named in the second paragraph of the "Identifying Forces" section?

(a)  

How is net force defined?

What type of friction exists in a stationary sofa?

(a)  

You have to specify a (a)   when you combine forces.

Aurora pushes a sofa with a force of 300 N to the right. She asked for help and Arthur pushes with a force of 200 N to the right. What is the net force applied to the sofa?

• 300 N to the right

• 500 N to the right

• 100 N to the left

• 100 N to the right

Two friends push a dresser from different directions. Sam pushes with a force of 700 N to the left and Fred does it with a force of 300N to the right. What is the net force applied to the dresser?

• 400 N to the left

• 700 N to the right

• 1000 N to the left

• 300 N to the right

Ramon and John makes a bet to see who is stronger. Using a 450 N force, Ramon pushes the drawer to the right. John pushing from the left, applies a 300 N force. However, seeing that his brother is about to lose, Don pushes with a force of 150 N to the left. What is the net force applied to the drawer?

• 150 N to the left

• 750 N to the right

• 450 N to the right

• 0 N

Forces acting on an object that combine and form a net force of zero are (a)   .