Physics help!!!?

Question

how far above earth's surface do i hav to be in order for my weight to be cut in half?

Answer 1

Half will be the answer and that is where gravity is halved.

Answer 2

According to Newton's law of universal gravitation, your weight on the Earth's surface is GMm/R^2, where G is the universal constant of gravitation, M is the mass of the Earth, m is your mass, and R is the radius of the Earth.  G, M, and m are all constant, so what you want to find is some r so that:

1/2*GMm/R^2=GMm/r^2

After you cancel out GMm on both sides and do some algebra, you wind up with:

r=R*2^(1/2)

I don't know R offhand, but you can look it up on Wikipedia or in most intro physics texts.  The value of r is how far away from the Earth's center you would need to be to halve your current weight, so just subtract R from that to find how far above the earth's surface you need to be.

Answer 3

there is this formula

g'/g=(1+h/r)^ -2

now here u want ur weight to be half so g'/g =2 as g' is the new g and the g is the standard one ur weight will change only when g changes.

r has a standard value of 6400kms. i guess put everything in it and get h.

if u dont get the answer sometimes this formula is modified when h is too small as compared to r

g'/g=(1-2h/r)

Answer 4

if R is the radius of the earth (distance from center to surface), then the force of gravity due to the earths mass M acting on your body mass m is what you feel as your weight, W. This gravity force goes to the inverse of the distance squared.

W = G m M / ( r * r)  

when you are at the surface r=R and that is your weight.

W_at_surface = G m M / (R*R)

when you are at some other distance, x= squareroot(2) R then your weight is halved:

W_at_x = G m M / (sqrt(2)*R * sqrt(2) *R) =  W_at_surface / 2

sqrt(2) is roughtly 1.41

so if you have roughly an altitude of  41% of an earth radius then you would weight half as much.

Answer 5

simple. as far up as a plane. then it will chop you in half and you are half the weight.