Science 8 Ch 9 Sec 1-2

An object moves 3 cm to the right, then 6 cm to the left, then 8 cm to the right. What is the object's final displacement from its origin?

5 cm to the right.

How are distance and displacement similar? How are they different?

Displacement is the length and direction that an object has moved from its starting point. They both refer to the length of two points but distance is the total length of the actual path between those two points. Displacement is the length and direction of a straight line and those two points.

What does the slope of a distance-versus-time graph show you about the motion of an object?

It shows you the speed of the moving object

Your car's speedometer reads a constant 35 mi/hr. Can you say the velocity is constant?

Probably not. It is likely that the direction your car is going is changing some of the time.

How do you calculate slope?

Slope= rise/run

How do you calculate speed?

Speed= Distance/Time

speed

The speed of an object is the distance the object travels per unit of time.

Suppose you are riding in a car. Describe your motion relative to the car, road and sun.

You are stationary relative to the car and moving relative to the road. As long as the car is moving in a straight line, the sun does not appear to move much in a short period of time. So, it appears that you are relatively motionless to the sun.

vector

a quantity that consists of both a magnitude and a direction.

motion

an object is in motion if its distance from another object is changing

Why is it important to know if your reference point is moving?

because it will be difficult to determine which direction you are moving in, if moving at all.

average speed

divide the total distance traveled by the total time

How do you know an object is moving?

if it changes its position relative to a stationary reference point

reference point

is a place or object used for comparison to determine if something is in motion

displacement

is the length and direction that an object has moved from its starting point

distance

is the length of a path between two points

instantaneous speed

is the rate at which an object is moving at a given instant in time.

velocity

is the speed in a given direction.

Describe two ways velocity can change.

it can change in speed or direction or both.

slope

the steepness of a line on a graph is called the slope