If element X has 39 protons, how many electrons does it have?

Which best identifies the requirements for work to be performed? an object that has a force acting on it an object that is moving and has no net force a force acting on a motionless object a force that moves an object

1. What are the approximate calorie needs of a sedentary 16 year old male? A. 1.800 calories C. 2,200 calories B 2.000 calories D. 2,400 calories

You place your hands over a steaming bowl of soup to warm them. Which type of heat transfer are you experiencing? A. Radiation B. Convection C. Insulation D. Conduction

The friction between surfaces that are stationary

Brett has an intense, irrational fear of needles and other sharp objects. Brett is most likely to be diagnosed with:

Are microwaves and radio waves faster or slower than other types of electromagnetic energy?

If you dive under-water, you notice an uncomfortable pressure on your eardrums due to the increased pressure. The human eardrum has an area of about 70 mm2 (7*10-5m2), and it can sustain a force of about 7 N without rupturing.

Why cant kinetic energy ever be greater than potential energy

For a stationary observer, when the source of a sound is moving, its pitch appears to change.

Give an example of each simple machine