Complete question is;
Shoveling snow can be extremely taxing since the arms have such a low efficiency in this activity. Suppose a person shoveling a sidewalk metabolizes food at the rate of 800 W. (The efficiency of a person shoveling is 3%.)
(a) What is her useful power output? (b) How long will it take her to lift 3000 kg of snow 1.20 m? (This could be the amount of heavy snow on 20 m of footpath.) (c) How much waste heat transfer in kilojoules will she generate in the process?
Answer:
A) P_out = 24 W
B) t = 1470 s
C) Q = 1140.72 KJ
Explanation:
We are given;
Input Power; P_in = 800 W
Efficiency; η = 3% = 0.03
A) Formula for efficiency is;
η = P_out/P_in
Making P_out the subject, we have;
P_out = η•P_in
P_out = 0.03 × 800
P_out = 24 W
B) We know that;
Power = work done/time taken
Thus;
P_out = mgh/t
We are given;
m = 3000 kg
h = 1.20 m
Thus, time is;
t = (3000 × 9.8 × 1.2)/24
t = 1470 s
C) amount of heat wasted is calculated from;
Q = (P_in - P_out)t
Q = (800 - 24) × 1470
Q = 1,140,720 J
Q = 1140.72 KJ
Answer:
C. equal to
Explanation:
1 Cubic meter (m³) is equal to 1000000 cubic centimeters (cm³). To convert cubic meters to cubic centimeters, multiply the cubic meter value by 1000000.
<span>The word is "pitch", which is exactly that: How "high" or "low" a sound is.</span>
Look at the third one i think its the answer
<span>The first stage in the Gas model of stress is alarm and
mobilization. So the correct option in regards to the given question is option “d”.
Hans Selye is the person that evolved this model and he has explained this
model in complete details. He has broken
down his model into three stages. The first stage involves alarm and
mobilization. The second stage includes resistance. The third and the final
stage include the exhaustion stage. These are the stages that an organism goes
through to restore back the balance when stress is exerted from outside. </span>
