<h3><u>Answer;</u></h3>
C) He could injure or pull a muscle.
<h3><u>Explanation</u>;</h3>
- <em><u>When muscles are stretched the muscle fibers are temporary lengthened. Muscles have a unique ability to undergo contraction and lengthening since they are elastic.</u></em>
- <em><u>When the muscles are warm they are more elastic, therefore, warming up the muscles is very important for the purpose of avoiding injuries.</u></em> Ir is important to engage in moderate cardiovascular warm-up prior to stretching, which increases the blood flow to the active and thus avoiding injuries to the muscles.
- Stretching muscles when they are cold may bring injuries or cause muscle pulls, which are painful.
<span>R = rate of flow = 0.370 L/s
H = height = 2.9 m
T= time = 3.9 s
V = velocity of water when it hits the bucket = sqrt(2gh) = sqrt(2 x 9.8 x 2.9) =7.539 m/s2
G value = 9.8 m/s2
Wb = weight of bucket = 0.690 kg x 9.8 m/s2 = 6.762 N
Wa = weight of accumulated water after 3.9 s
Fi = force of impact of water on the bucket
S = reading on the scale = Wa + Wb + Fi
mass of water accumulated after 3.9 s = R x T = 0.370 x 3.9 = 1.443 L = 1.443 kg
Therefore, Wa = 1.443 x 9.8 = 14.1414 N
Fi = rate of change of momentum at the impact point = R x V (because R = dm/dt)
= 0.37 x 7.539 = 2.78943 N
S = 14.1414 + 6.762 + 2.78943 = 23.692 N</span>
C is the first & the second question is A
Answer:
1. W = F d = 20 N * 6 m = 120 J
2. F = W / d = 60 J / 2 m = 30 N
3. d = W / F = 350 J / 85 N = 4.12 m
4. P = W / t = F d / t = 45 N * 9 m / 10 s = 40.5 Watts
5. W = P t = 500 W * 120 sec = 60,000 J
6. t = W / P = 550 J / 310 W = 1.77 sec
The height difference is found by
Then the change in potential energy is
