In the 1920s what did Edmund hubble notice about the galaxies

Which of the changes occurs when energy is absorbed?

A machine runs for 50 seconds with a steady power output of 100 watts. How many joules of work does the machine produce in those 90 seconds?

A lithium atom has three electrons. a fluorine atom has nine protons and nine electrons, with seven electrons in its outer energy level.

Why is it better to build and test a prototype of a product than to pruduce tens of thousands of the product and then test it?

According to Newton's third law of motion when a hammer strikes and exerts force on a nail to push it into a piece of wood the nail

The speedof a boat in still water is v. The boat is to make a round-trip ina river whose current travels at speed u.

Why are there so few working wave power stations?

Two abiotic factor that effect an ecosystem are;

Which of the following is explained by general relativity? A. How massive stellar objects can form a lens. B. Why moving muons decay more slowly than stationary ones C. Why atomic clocks tick more slowly when in motion D.

Imagine that you're observing a collision. Which action would allow you to determine whether the collision is inelastic? A. Measure the force of impact. B. Observe whether the colliding objects change their shape. C.