A rocket is shot from the top of a cliff 300m above sea level with a velocity u at an angle of 45° to the
horizontal.
e
(a) What time does the rocket take to hit a boat after
it has been fired. Take g = 10 ms?
(b) What is the value of 'u' if the rocket hits the boat
4.2km away on the sea.​

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.