A) it occurs when earth is between the sun and the moon
Answer:
Option A. 40 mi/h
Explanation:
To obtain the average speed of the vehicle, we'll begin by calculating the distance travelled by the vehicle in each case. This is illustrated below:
Case 1:
Speed = 30 mi/h
Time = 2 h
Distance =...?
Speed = Distance /Time
30 = Distance /2
Cross multiply
Distance = 30 × 2
Distance = 60 mi
Case 2:
Speed = 60 mi/h
Time = 1 h
Distance =...?
Speed = Distance /Time
60 = Distance /1
Cross multiply
Distance = 60 × 1
Distance = 60 mi
Finally, we shall determine the average speed of the vehicle as follow:
Total distance travelled = 60 + 60
Total distance travelled = 120 mi
Total time = 2 + 1
Total time = 3 h
Average speed =..?
Average speed = Total Distance travelled /Total time
Average speed = 120/3
Average speed = 40 mi/h
Therefore, the average speed of the vehicle is 40 mi/h
Missing question: "how much work is done by the teacher?" (found on internet)
Solution:
The work done to move the desk across the floor is equal to
where F is the horizontal force applied to move the desk, and d is the distance covered by the desk. If we use F=20 N and d=5 m, we find the work done:
I believe destructive interference.
EXPLANATION: when two waves meet and a crest of one wave is parallel to the crest of another destructive interference occurs. You subtract the amplitude of the two waves that meet and you’ll get the amplitude of the wave they’ll form. If it is the same amplitude the result will be zero.
Hope this helps
<span>Whatever the focus of the experiment is, plus any others factors that might influence the outcome of the experiment. If you are testing a new cancer drug, the experimental group and the control group must both be people with the same type of cancer, and both be a representative distribution of the population, all races, genders, ages, etc. You want the only difference in the two groups to be what you are studying, i.e. the effects of the drug.</span>
