weight, mass and gravity

what is gravitational force?

the force of attraction between masses

why do we only notice gravity when one of the masses is very big?

because the force of attraction is stronger for large masses, like planets

what are the two important effects of gravity on a planet’s surface?

it makes all objects fall towards the ground, and it gives everything weight

what is the difference between mass and weight?

mass is the amount of matter in an object and stays the same, while weight is the force due to gravity and changes depending on location

what is weight caused by?

the gravitational pull on an object

why does an object weigh less on the moon than on earth?

because the gravitational field strength on the moon is weaker than on earth

what is the equation for weight?

weight (n) = mass (kg) × gravitational field strength (n/kg)

what is the gravitational field strength on earth?

9.8 n/kg

what is the gravitational field strength on the moon?

1.6 n/kg

how are mass and weight related?

they are directly proportional—if mass doubles, weight doubles

what is the unit of weight?

newtons (n)

what is the unit of mass?

kilograms (kg)

what is the weight of a 5 kg mass on earth?

49 n

what is the weight of a 5 kg mass on the moon?

8 n