Calculate the total Gravitational Potential Energy (GPE) of a 10 kg birdhouse at a height of 25 meters using gravity's average acceleration of 9.8 m/s2
GPE = mxgxh
A. 25,000 J
B. 35 J
c. 2,450 J
D. 250 J

What is hidden during a lunar eclipse? isn't the moon hidden?

When you drop a pebble from height a it reaches the ground with speed v if there is no air resistance. from what height should you drop it so it will reach the ground with three times the speed? (a) 9m (b) 3m (c) 6m (d) 18m

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.