Unit 1 General physics
The relationship between weight, mass and gravitational field strength can be expressed as:W=mg
W = weight (N) m = mass (kg) g = gravitational field strength (N/kg)
- On Earth the gravitational field strength is 10N/kg.
- Because g is a constant near to Earth, the weight of an object is proportional to its mass.
- If mass doubles, weight doubles. It follows that weights may be compared using a mass balance.ExampleOn Earth a man has a mass of 85kg. Calculate his weight.
List all the information in symbol form and change into appropriate and consistent SI units if required.
Use the correct formula.
Calculate the answer by putting the numbers into the formula.
W=mg=85 × 10=850N
W = mg = 85 × 10 = 850N
ALWAYS REMEMBER TO STATE THE UNIT FOR CALCULATED QUANTITIES.