Sem 2 Unit 1 Review

What is Newton's first law of motion?

• Energy can neither be created nor destroyed.

• The acceleration of an object is directly proportional to the net force acting on it.

• An object at rest will remain at rest, and an object in motion will continue in motion with the same speed and direction unless acted upon by an unbalanced external force.

• For every action there is an equal and opposite reaction.

Which of the following most completely describes an object's motion?

Hint: Scientists describe motion by including details of displacement AND time.

• A car travels 30 miles.

• The rain falls at a rate of two inches per hour.

• A marble rolls 20 m to the right.

• The baby crawls 15 feet in 25 seconds toward the door.

A cyclist rode at an average speed of 10 mph for 15 miles. How long was the ride?

Hint: s = d / t

• 1.5 hours

• 10 hours

• 15 hours

• 150 hours

Inertia increases as an object's _________ increases.

• velocity

• mass

• volume

• acceleration

Billy gets up from his seat on a moving bus to move closer to the front for his stop. Just as he begins to walk, the bus comes to a quick stop. What is the best explanation for what happens to Billy?

• While Billy is walking, his body is in motion. When the bus stops, because he's not buckled, Billy continues to move forward due to inertia.

• While Billy is walking, his body is in motion. When the bus stops, an unbalanced force accelerates his body backwards.

• While Billy is walking, his body is in motion, but as the bus stops, it exerts a force on Billy opposite to the direction he is walking, causing him to stop as well.

• While Billy is walking, he is in motion due to the force of repulsion. When the bus stops, he is catapulted forward due to the bus' stronger force of attration.

Which of the following answers describes how to calculate the acceleration of an object?

• Calculate the distance the object travels and divide that by the time it takes to get there.

• Calculate the velocity of an object and divide that by the time the object is in motion.

• Divide the time the object travels by the distance it travels.

• Divide the change in the object's velocity by the time it takes to make that change.

Which of the following answers best describes how velocity and acceleration are related?

• Acceleration is another word for velocity.

• Velocity is the rate of change in acceleration.

• Acceleration is the rate of change of velocity.

• Acceleration is always negative, and velocity is always positive.

A car traveled at an average speed of 65 mph for 10 hours. How far did it travel? Hint: s = d / t

• 10 miles

• 65 miles

• 650 miles

• 6, 500 miles