Eric stretches out his calf muscles by pushing against a stationary 4000 kg wall with a force 300 N. How much work is done?

4000*300=1200000

Explanation:

work done formula

W = F * d:

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.