A sample of a radioactive elements must contain atoms

A.

with a stable nuclei

B.

with unstable nuclei

C.

in the excited state

D.

in the ground state

What is the difference between Groups and Periods?

Which could describe the motion of any object

Why would it appear that the sun does not rise during the winter solstice at 66 degrees latitude? (Consider the tilt of the earth during that season)

What are the differences between speed, velocity, and acceleration?

If 2500 joules of work are needed to move a car a distance of 5 meter what is the force on the car

Suppose a body has a mass of 60 kilograms and a velocity of 2 meters per second upward. What is the linear momentum?

Reflection and abssorption prevent some

Why is it important to change only one experimental variable at a time in an experiment?

A 0.0663 kg ingot of metal is heated to 241◦C and then is dropped into a beaker containing 0.395 kg of water initially at 25◦C. If the final equilibrium state of the mixed system is 27.4 ◦C, find the specific heat of the metal.

What does it mean when we say an atom has decayed?