30 pts What are some of the difficulties with measuring the volume of a gas? Select all that apply. A. it could be soluble in liquid
B. it varies depending on the container it is in
C. it varies based on its mass
D. it can be difficult to contain.

The focal length of a relaxed human eye is approximately 1.7 cm. when we focus our eyes on a close up object, we can change the refractive power of the eye by about 16 diopters. (a) does the refractive power of our eyes increase or decrease by 16 diopters when we focus closely? explain. (b) calculate the focal length of the eye when we focus closely.

If the work required to stretch a spring 3 ft beyond its natural length is 15 ft-lb, how much work is needed to stretch it 27 in. beyond its natural length?

What type of force holds atoms together in a crystal?