If a pendulum has a period of 2.4 seconds what is the frequency?

What defines the mass number of an isotope? a. the sum of the neutrons and protons b. the sum of the neutrons and electrons c. the number of neutrons d. the number of protons

How many dots must be added to the symbol to properly represent a standard nitrogen ion? a) 1 b) 3 c) 5 d) 8

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is