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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: generalkorn12 on July 29, 2012, 10:05:38 am

Title: Forces Acting on a Falling Object
Post by: generalkorn12 on July 29, 2012, 10:05:38 am

Hi,

I have trouble understanding what kind of forces act when objects are falling, I know weight force, and air resistance (if it applies) occurs, but is it alright to always assume (regardless of the question) that, 'g' is also acting?
I've got doubts about it, because my teacher seems to neglect using 'g' sometimes..

Thanks.

Title: Re: Forces Acting on a Falling Object
Post by: max payne on July 29, 2012, 10:12:22 am

'g' is the value of acceleration of acceleration of a body due to gravity. Unless otherwise stated, assumed to be 9.8m/s^2 (the value of gravitational acceleration at the surface of the earth). The weight force acting on a falling body is equal to mass*g and yes you should assume that gravity is acting on a falling object because without it, thered be no point to the question.

Title: Re: Forces Acting on a Falling Object
Post by: abeybaby on July 29, 2012, 11:13:31 am

'g' is not a force acting on the object.

the object will definitely have a weight force of magnitude mg. forces induce acceleration. regardless of the mass of the object, using F=ma you get that the acceleration caused by the weight force is mg=ma so a=g, ie,

FORCE due to gravity =mg
ACCELERATION due to gravity =g, regardless of the value of m.