Gravitational field strength formula

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To calculate the gravitational field strength at a height of 350 km above the Earth's surface, the formula g = GM/r² is used, where G is the gravitational constant and M is the mass of the Earth. The Earth's radius is approximately 6700 km, so the total distance from the center of the Earth to the point of interest is 6700 km + 350 km, which must be converted to meters. The correct calculation involves substituting these values into the formula to find g. It is crucial to ensure that all distances are in meters to achieve an accurate result, which should approximate 9 N/kg.
g33n13
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Q: "The Earths radius is 6700km. Show that the magnitude of the gravitational field strength at a height of 350km above the Earth's surface is about 9 N/kg"

I got the mass of the Earth which is 5.98E 24
G the constant = 6.67E -11

Formula : g= GM/r² , i can't seem to get 9, am I supposed to use the 350km??
 
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Yeah, at a distance R away, the gravitational force is

mg = \frac{GMm}{r^2}

Your distance R is 350km above the Earth's surface .
 
Make sure your 350km is in metres!
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
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