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
In Newton's Third law of motion, the 'action' and 'reaction' forces act on different objects. That's why they don't cancel each other out and always result in zero force.
Answer:
Centripetal acceleration = 83.77m/s²
Explanation:
<u>Given the following data;</u>
Radius, r = 0.13m
Velocity, v = 3.3m/s
To find centripetal acceleration;
Centripetal acceleration is given by the formula;
Substituting into the equation, we have;
<em>Centripetal acceleration = 83.77m/s²</em>
<em>Therefore, the centripetal acceleration of the edge of the disc is 83.77 m/s². </em>
Here's the equation you use: Density = mass/volume
1) 5.2g/cm^3 = m/3.7cm^3
2) m = 5.2g/cm^3 x 3.7cm^3
3) m = 19.24g
You can check the answer by plugging it in
19.24g/3.7cm^3
= 5.2g/cm^3
Since the bag was at rest, its initial momentum is zero. The velocity of the ball before collision is 500 ms-1.
<h3>Linear momentum</h3>
The term momentum in physics refers the product of mass and velocity. If we know mass of the object and its velocity, then we calculate the momentum.
Momentum before collision for the bullet = 0.01 kg × v
Momentum before collision for the bag = 0
Momentum after collision for the bag and bullet = (0.01 kg + 0.49 kg) 10 = 5 Kgms-1
The velocity of the bullet before collision = 0.01 kg × v + 0 = 5 Kgms-1
v = 5 Kgms-1/0.01 kg
v = 500 ms-1
Learn more about momentum: brainly.com/question/904448
