A supertrain of proper length 200 m travels at a speed of 0.9 times the speed of light (relative to the tunnel) as it passes through a tunnel having proper length 80 m. In the reference frame of the tunnel, how much longer is the train than the tunnel

The softest and hardest minerals are: softest hardest

During a medieval siege of a castle, the attacking army uses a trebuchet to hurl heavy stones at the castle walls. if the trebuchet launches the stones with a velocity of at an angle of 50.0°, (a) how long does it take the stone to hit the ground? (b) what is the maximum distance that the trebuchet can be from the castle wall to be in range? (c) how high will the stones go? show all your work.

Which describes increasing the efficiency of energy resource