The idea that "students ' immune systems have declined due to the use of hand sanitizers " is a hypothesis.
The term hypothesis refers to an intelligent guess or idea often based which is subject to scientific investigation via experiments.
A hypothesis may be right or wrong. We can only prove a hypothesis by subjecting it to a series of rigorous experiments.
Thus Collette's idea is a hypothesis.
Learn more: brainly.com/question/18284466
Answer:
a) The velocity is 2.94m/s
b) 0.441
Explanation:
a) Assume gravity is 9.8m/s^2
Use the equation below to solve for the velocity at 0.30 seconds
,
vf =unknown velocity vi= initial velocity vi=0m/s a= 9.8m/s^2 t=0.30seconds
Step 1: Substitute the variables with the knowns

Step 2: Solve

b)
Use the equation below to solve for the displacement at 0.30 seconds

Step 1: Substitute the same variables with the knowns

Note that vi*t=0 as vi=0m/s
Step 2: Solve
x=0.441m
Answer:
Average speed = 1.2 m/s
Average velocity = 0.4 m/s
Explanation:
Average speed = total distance/total time
Average speed = (40 + 20)/(40 + 10)
Average speed = 60/50
Average speed = 1.2 m/s
Average velocity = displacement/time
Now, she ran 40 m south and ran 20 m back north which is in the direction of where she began the journey.
Thus;
Displacement = 40 - 20 = 20 m
Average velocity = 20/50 = 0.4 m/s