# FALLING OBJECTS

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Falling objects

Weight- force of gravity on it. measured in newtons.

Mass- quantity of matter inside an object. measured in Kg.

• 1KG = 10N

- force of gravity on a 1KG object: GRAVITATIONAL FIELD STRENGTH (N/kg)     if we know the mass, we can calculate the weight:

WEIGHT= MASS x GRAVITATIONAL FIELD STRENGTH

GFS is always 10 so -->

1) calcuate the weight in N of a person of mass 55Kg= 55 x 10= 550N

W = mg

where:

w= weight in newtons (N)

m= mass in kg

g = GFS (n/kg)

if an object falls with NO OTHER forces acting on it, the resultant force (N) = (mass x acc.) will be its weight. - because this is what is making it accelerate downwards.

It will then accelerate constantly down at 10m/s squared. = ACCELERATION DUE TO GRAVITY.

eg 1 kg object above the ground: the force of gravity is 10N (coz 1kg=10N) and so its acceleration ( by re-arranging the equation we get force/mass= 10N/1KG)=    10m/s squared.

Objects falling through fluids- objects falling through air, liquid

Drag Force- a force opposing the motion of an object as it goes through a fluid such as air or liquid (the force that makes it go up)

- increases with speed

- so the resultant force (overall force)