8-3 Dot Product and Vector Projections

Which of the following pairs of vectors are orthogonal?

• 30.5 degrees
• 90 degrees

• 45 degrees

• 60 degrees

• 〈0,0〉
• 〈-5,5〉
• 〈-1,1〉
• 〈2,3〉

• Acute angle
• Right angle
• Straight angle
• Obtuse angle

• 5
• -6
• 15
• 10

• 12
• 0
• 9
• -3

• 13
• 15
• 20
• 10

A person pushes a car with a constant force of 120 newtons at a constant angle of 45° as shown. Find the work done in joules moving the car 10 meters.

• 848.53 joules
• 1000 joules
• 500 joules
• 300 joules

Ahmed is pushing a vacuum cleaner with a force of 375 newtons. The handle of the vacuum cleaner makes a 60° angle with the floor. How much work in newton-meters does he do if he pushes the vacuum cleaner 2 meters?

• 375 N·m
• 3750 N·m
• 500 N·m
• 250 N·m