An athlete does one push-up. in the process, she moves half of her body weight, 250 newtons, a distance of 20 centimeters. this distance is the distance her gravity moves when she fully extends her arms. how much work did she do after one push-up?

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

Consider a 1000 w iron whose base plate is made of 0.5 cm thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp = 875 j/kg°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90% of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.

What causes the development of most clouds and precipitation in the atmosphere?