A heat engine has a cold reservoir of 250°C and a hot reservoir of 715°C. What is the efficienvy of the engine?

A binary star system in the constellation orion has an angular separation of 10-5 rad. if the wavelength of the light from the system is 500 nm, what is the smallest aperture (diameter) telescope that can just resolve two stars?

Can a twig float on water?

D=v^0 t+1/2 at^2 the 0 is supposed to be really small right next to the v under it

How long does it take before dolphins become adults ready to have young themselves?

geography Which nation in the region has seen its growth rate accelerate, while the majority of the region has seen a decline in growth rates?

a man applies a force of 100n to a rock for 60 seconds but the rock does not move what is the amount of work done by the man on the rock

The driver of a car traveling at 32 m/s applies the brakes and undergoes a constant deceleration of 2.25 m/s^2.

You are going to develop some photographic film that involves a chemical reaction between the developer, which you will mix yourself, and a chemical on the surface of the film.

Would time travel mean that parallel universes would be created off our linear time sequence to ensure the universe doesn't collapse itself because of significant events being drastically changed in the way it shapes the universe?

What is the central core of hair