A low-frills patio or deck is pretty cheap. Everyone's definition of cheap is different, but decks can be had for as low as $1,000, according to Jessica Piha, a spokeswoman for Porch.com, a website that helps homeowners find the right contractor. But the average deck costs $8,300, Piha says. And how much is a cheap patio? The cost to install a 200-square-foot concrete patio is about $740 to $840 on average, according to HomeWyse.com, an online reference for home projects. But here's why you probably won't buy a cheap patio. If you're pining over someone's patio, you presumably don't want a concrete slab.
The acceleration due to gravity on the surface of the Moon. The mass of the Moon is 7.35 x 10^22 kg and the average radius of the Moon is 1.74 x 10^6 m. Plugging into the formula, we have: g = (6.67 x 10^-11 N-m^2/kg^2)(7.35 x 10^22 kg )/(1.74 x 10^6 m)^2 = (4.9 x 10^12 )/(3.03 x 10^12) = 1.6 m/s^2.
Now, all mass exerts a gravitational force, and the tidal bulges on the Earth exert a gravitational pull on the Moon. Because the Earth rotates faster (once every 24 hours) than the Moon orbits (once every 27.3 days) the bulge tries to speed up the Moon, and pull it ahead in its orbit. The Moon is also pulling back on the tidal bulge of the Earth, slowing the Earth's rotation.