PS Test 6 (7th) 21-22

An object is moving if

• the distance to a reference point is changing

• the distance to a reference point is not changing

• none

A reference point should be

• a moving object

• a non-moving object

• none

Explain what rate of change means

Speed is

• the distance covered in a unit of time

• the time covered in a unit of distance

• none

Which of these are units of speed?

• m/s , km/h, MPH

• m , km, cm

• none

 $\frac{dista\eta ce}{time}$  

• acceleration

• speed

• none

If we want to increase a car's speed from 30 m/s to 40 m/s

• we must accelerate

• we must not accelerate

• none

 $\frac{speed}{time}$  

• acceleration

• speed

• none

An object is accelerating when

• its speed is changing in a unit of time

• its speed is not changing in a unit of time

• none

Acceleration can be

• positive or negative

• big or small

• none