A simple pendulum is made of a mass mounted onto a rod. It oscillates at a frequency f. By what factor would the frequency of the pendulum change if the distance between the mass and the pendulum's pivot doubled，assuming the pendulum rod has negligible mass？

Which lists the main components of darwin’s theory of evolution? a. random mutations drive evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms do not change. b. natural selection drives evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms change over time. c. natural selection drives evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms change over time. d. random mutations drive evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms do not change.

Which of the following harmful chemicals are found in tobacco smoke? a. carbon monoxide b. carbon dioxide c. nicotine b. carbon dioxide d. both a and c

Which changes would result in a decrease in the gravitational force btween two objects? check all that apply