A G main sequence star spends far more time on the main sequence than an O main sequence star because

Why is it dangerous to be exposed to X-rays but not (or at least much less) dangerous to be exposed to radio waves?

As a basketball player starts to jump for a rebound, he begins to move upward faster and faster until he leaves the floor.

A box is dropped onto a conveyor belt moving at 4.0 m/s. If the coefficient of friction between the box and the belt is 0.40, how long will it take (in s) before the box moves without slipping

An article in a magazine states that the people who work in uranium mines are likely to suffer from diseases. Which of these is the most reliable method to verify the information provided by the magazine? a.

A young girl gives her toboggan a push of 4.0m/s uphill. It slides up the hill slowing down at an acceleration of 8.0m/s down. It comes to a stop and then slides back towards her speeding up at the same rate as it slowed down on the way up.

A turntable is spinning on a frictionless axle when a ball of putty is dropped onto it from above. The putty sticks to the turntable when it lands. Is angular momentum conserved for the turntable and putty (the system) during this process?

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.