Studies in Science

SI Base Units

In Physics we always work in the Base SI units. So
always convert to MKS, Metres, Kilograms and Seconds.

Length ---- Metre (m)
Mass ---- Kilogram (kg)
Time ---- Seconds (s)

Factor Label Conversions

Conversion between metric units and imperial units

Length

1 metre (m) = 100 centimetres (cm)
1 metre (m) = 1000 millimetres (mm)
1 metre (m) = 3.281 feet
1 foot (ft) = 0.3048 metres
1 yard = 3 feet = 0.914 m
1 metre = 1.09 yards
1 mile = 1760 yards = 1606.344 m = 1.6 km
1 km = 0.621 miles (1 km is about 5/8 of a mile)

Time

1 minute (min) = 60 seconds (s or sec)
1 hour (hr) = 60 minutes (min)
1 hour (hr) = 3600 seconds (s or sec)
1 Day = 24 hr
1 year = 365 Day

Area

1 square metre = 10.764 square feet = 1.196 square yards
1 square yard = 0.836 square metres
1 square foot = 0.0929 square metres

Mass

1 kilogram (kg) = 1000 grams (gm or gr or g)
1 kilogram (kg) = 2.205 pounds (lb)
1 lb = 0.454 kilograms
1 ounce (oz) = 0.0283 kg = 28.3 grams (gm)

Volume

1 cubic metre = 35.3 cubic feet 1 cubic foot = 0.0283 cubic metres = 6.21 gallons
1 gallon = 0.00456 cubic metres = 4.56 litres = 0.16 cubic feet
1 litre = 0.22 gallons = 0.26 gallons (USA)
1 cubic centimetre (cc) = 1 millilitre (ml)
1 litre (l) = 1000 cubic centimetre (cc)
1 gallon (USA) = 0.00379 cubic metres = 3.79 litres

Power

1 Horse power (HP) = 746 W
1 W = 0.0013 HP

Useful speed limits:
20 mph = 32 km per hour
30 mph = 48.2 km per hour
60 mph = 96.4 km per hour
70 mph = 112.4 km per hour

20 km per hour = 12.5 mph
30 km per hour = 18.7 mph
40 km per hour = 25.0 mph
50 km per hour = 31.1 mph
60 km per hour = 37.4 mph
70 km per hour = 43.8 mph
90 km per hour = 56.0 mph
110 km per hour = 68.5 mph
120 km per hour = 74.7 mph
130 km per hour = 80.9 mph

Acceleration
Standard acceleration of gravity = 9.81 m/s2