Motion, Distance, Displacement, Speed & Velocity

Define motion

A change in an object's position relative to a reference point

What is a frame of reference

A system used to determine an object's position and motion

What is distance

The total length of the path an object travels

What is displacement

The change in position from the starting point to the ending point including direction

What is the difference between distance and displacement

Distance measures the entire path while displacement measures the change in position with direction

What is a scalar

A quantity with magnitude only

What is a vector

A quantity with magnitude and direction

Is distance a scalar or vector

Scalar

Is displacement a scalar or vector

Vector

Is speed a scalar or vector

Scalar

Is velocity a scalar or vector

Vector

What is the formula for average speed

Speed = total distance divided by total time

What is the formula for average velocity

Average velocity = displacement divided by elapsed time

What is the SI unit for speed and velocity

Meters per second (m/s)

A runner travels 180 m in 30 s. What is the average speed

6 m/s

A runner moves 100 m east and then 40 m west in 20 s. What are the distance and displacement

Distance = 140 m. Displacement = 60 m east

A student walks 80 m north and then 80 m south in 40 s. What are the average speed and average velocity

Average speed = 4 m/s. Average velocity = 0 m/s

A car travels 150 m at an average speed of 10 m/s. How long does it take

15 s

A cyclist travels for 25 s at 8 m/s. How far does the cyclist travel

200 m

A person travels 300 m in 60 s and then 100 m in 20 s. What is the average speed for the entire trip

5 m/s

Two cars travel at 20 m/s. One moves north and one moves south. Do they have the same velocity

No. Their velocities have opposite directions

Can an object have zero displacement but nonzero distance

Yes. It can travel and return to its starting point

Can an object have constant speed but changing velocity

Yes. Changing direction changes velocity

A student says a car's speed is 15 m/s east. What is wrong with the description

East is a direction, so the quantity described is velocity

A car's displacement is 240 m west over 12 s. What is its average velocity

20 m/s west

A student walks 60 m east in 10 s then 60 m west in 10 s. What is the average velocity for the entire trip

0 m/s