## College Physics (4th Edition)

An object with a mass of $5.9~kg$ that is near the Earth's surface would have this magnitude of gravitational force exerted on it.
We can find the electric force: $F = \frac{k~q_p~q_p}{r^2}$ $F = \frac{(9.0\times 10^9~N~m^2/C^2)~(1.6\times 10^{-19}~C)(1.6\times 10^{-19}~C)}{(2.0\times 10^{-15}~m)^2}$ $F = 57.6~N$ We can find the mass of an object near the Earth's surface with this magnitude of gravitational force: $F = ma$ $m = \frac{F}{a}$ $m = \frac{57.6~N}{9.80~m/s^2}$ $m = 5.9~kg$ An object with a mass of $5.9~kg$ that is near the Earth's surface would have this magnitude of gravitational force exerted on it.