Because it needs sunlight to proceed, what type of reaction is photosynthesis?
a. exothermic b. electric c. endothermic d. combustion

An object has a weight of 500 on earth what is the mass of this object

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?