What is used to measure the mass of an object ?

Which branches of natural science include the study of an organism that lived 10 million years ago

An isotope undergoes radioactive decay by emitting radiation that has a –1 charge. what other characteristic does the radiation have?

Aturntable that spins at a constant 74.0 rpm takes 3.10 s to reach this angular speed after it is turned on. find its angular acceleration (in rad/s2), assuming it to be constant, and the number of degrees it turns through while speeding up.