Spaceship A moves at 0.800 in the positive - direction, while spaceship B moves in the opposite direction at 0.750 (both speeds are measured relative to Earth). What is the velocity {A, B} of spaceship A relative to spaceship B?

we need to know the time interval during which the force acts. impulse of force = momentum change

a.   mass number from atomic number

energy can be converted from one form to another, but it cannot be created or destroyed in ordinary chemical or physical means. do not understand what you are asking but hope this

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.