Motion and Forces

Judy’s brand new red Lamborghini car travels 280 kilometers in 4 hours. What is its average speed?

(Hint: speed = distance / time)

• 140 km/hr

• 280 km/hr

• 1120 m/hr

• 70 km/hr

Mary pushes a crate with a force of 50 N and a mass of 10 kg. What is the acceleration of the crate?

(Hint: acceleration = force / mass)

• 5 m/s²

• 30 m/s²

• 10 m/s²

• 7 m/s²

Cathy is in an airplane that takes off from Boston for the 980 km trip to Detroit. The plane lands two hours later. Which of the following best describes the average speed and direction of the airplane’s flight?

• 325 km/h West

• 490 km/h West

• 980 km/hr West

• 1960 km/h West

Are the forces on the bowling bowl balanced or unbalanced? What is the net force acting on the object?

• balanced, net force zero

• unbalanced, net force zero

• unbalanced, net force 50 N

• unbalanced, net force of 70 N

The graph shows distance to time for one of Anna’s swimming races. What is Anna’s average speed?

• 2 m/s

• 6 m/s

• 8 m/s

• 72 m/s

What is a force?

• a Jedi's Power

• only a push

• only a pull

• a push or a pull on an object

Define gravity.

• Gravity is less on the moon

• Gravity is an upward force that propels us into space.

• Gravity is a downward force that pulls use towards the center of the earth.

• Gravity does not exist.

A bug travels up a tree, from the ground, over a 30-second interval. It travels fast at first and then slows down. It stops for 10 seconds, then proceeds slowly, speeding up as it goes. Which sketch best illustrates the bug’s distance from the ground over the 30-second interval?

• a

• b

• c

• d

For an object to remain at rest, which of the following must be true?

• The forces on it are balanced.

• There is no friction.

• Gravity does not act on it.

• The object has no mass.

What is the force that resists motion between two surfaces that are in contact?

• gravity

• friction

• inertia

• resistance