Speed, Density & Pressure Flashcards

All 6 cards in this deck

What is the formula for speed?

Speed = distance $\div$ time.

True or false? Average speed is the total distance divided by the total time.

True.
It is not the average of the separate speeds.

What is the formula for density?

Density = mass $\div$ volume.
e.g. measured in g/cm$^3$ or kg/m$^3$.

What is the formula for pressure, and how do you find force or area from it?

Pressure = force $\div$ area; force = pressure $\times$ area; area = force $\div$ pressure.

What are the steps to find the time for a journey from its distance and average speed?

e.g. 36 km at an average speed of 16 km/h

1. Time $=$ distance $\div$ speed: $36 \div 16 = 2.25$ hours
2. Multiply the decimal part by 60: $0.25 \times 60 = 15$ minutes
3. Write the answer: 2 hours 15 minutes

What is the formula for distance when you know the average speed and the time?

e.g. 55 mph for 2 hours

Distance $=$ speed $\times$ time.

e.g. $55 \times 2 = 110$ miles