ANSWER

EXPLANATION
Parameters given:
Mass of the student, M = 70 kg
Mass of the textbook, m = 1 kg
Distance, r = 1 m
To find the gravitational force acting between the student and the textbook, apply the formula for gravitational force:

where G = gravitational constant
Therefore, the gravitational force acting between the student and the textbook is:

That is the answer.
Answer:
<u><em>A. wavelength</em></u>
Explanation:
The others are about sound and how high it is. That has nothing to do with time.
So that we do not contaminate it with microorganisms or garbage or other human stuff.
Answer:
A model rocket is launched with an initial upward velocity of 215 ft/s.
Explanation: