A space ship is observed to be length-contracted by a factor of 1/2. How fast is the space ship traveling, compared to the observers who noticed that it was length-contracted

If you mix chlorine lithium and nickel together which two elements would be the most reactive

Aball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and passes the top of the window 0.20 s later. the window is 2.0 m high from top to bottom. what was the ball's initial velocity? the unit vector j^ is directed upward. how far is the bottom of the window from the launch position? how high does the ball rise above the launch position?

Asystematic approach to problem solving is called a (an)