Question

You weigh 620 N. What would you weigh if the Earth were three times as massive as it is and its radius were four times its present value? Answer in units of N

Answer 1

if

Step-by-step explanation:

weight is the force of gravity on a mass; the force of gravity is

F = G M m/r^2

F is grav force

G is the newtonian gravitational constant = 6.67 x 10^-11 Nm^2/kg^2

M=mass of the earth

m=mass of the object

r= radius of the earth

if the mass of the earth increases by a factor of 6, this will tend to increase the grav force by a factor of 6

if the radius increases by a factor of 5, this will change the grav force by a factor of 1/5^2 = 1/25

the total effect is 6/25 = 0.24; therefore, your weight would be 0.24 * 620N = 149N