For this case we have the following equation:

Where,
w: The weight of a spring in pounds
E: the energy stored by the spring in joules.
Substituting values we have:

Making the corresponding calculation:
Answer:
the approximate weight of the spring in pounds is:
How many times do 15 minutes fit into one hour? 4 times: 4*15=60 mins.
So that means that 4 times per hour 10 flights appear, and in total 4*10=40 planes arrive over one hour!
Answer:
b. donations using text message
d. donations using email
Step-by-step explanation:
From the question, it is clear that the people who received these requests were assigned to two groups and these 2 were assigned treatments of if they make donations after either receiving email or text messages after which their respective proportions p1 and p2 are determined.
Do you have an example of what the "Constant of proportionality" would be for a different question?