If humans only have three kinds of color photo-receptors, how can we see so many different colors?

What are the dimensions of a square that has an area of 4cm^2

On another planet gravity has a value of 5.5 m/s. If an object is dropped how long will it take to fall 53 m?

Which of these is a compound? A: O B: CO2 C: O2 D: Co

How much heat is absorbed by a 34g iron skillet when its temperature rises from 11oC to 26oC?

The impulse of a constant force is equal to

How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 4.57*10-21 newtons?

If you could see the electric field coming off a proton you would notice that electric field lines are

We wrap a light, nonstretching cable around a 10.0 kg kg solid cylinder with diameter of 38.0 cm cm. The cylinder rotates with negligible friction about a stationary horizontal axis. We tie the free end of the cable to a 14.

A 0.5kg baseball experiences a 10N force for a duration of 0.1s. What is the change in velocity of the baseball

A beam of light passes from air into a cube of zirconium if the angle of incidence is 40"what is the angle of refraction?