Superman is flying 54.5 m/s when he sees a train about to fall into a river 850 m
away. He must reach the train in 4.22 s.
What acceleration does he need?
(Unit = m/s^2)

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.

Use the library or internet to research each planet. make a chart comparing the following: approximate surface temperature relative surface gravity compared to earth atmospheric gases water in any form: solid, gas, or liquid when you have completed your chart, use the information you have collected to answer the following questions: which is the hottest planet? which is the coldest planet? which planet's temperature is closest to that of earth? (note: water boils at 100°c/212°f. water freezes at 0°c/32°f) which planet has the greatest gravitational attraction? which planet has the least gravitational attraction? which planet's gravitational pull is closest to that of earth? do any of the planets have oxygen in their atmosphere? which planet's atmosphere most resembles that of earth? do any of the planets have flowing water? which planet's water resources (solid, gas, or liquid) might be close to the amount on earth? which planet most resembles earth in terms of all of the factors: temperature, gravity, atmosphere, and water? if earth became an uninhabitable planet, which planet do you think would be the next best to live on? explain your answer.