2.Cotton, polyester, nylon, rayon or can also be made by wool
ans D. Substance B has a greater latent heat of vaporization than substance A.
Answer:
a. v₁ = 16.2 m/s
b. μ = 0.251
Explanation:
Given:
θ = 15 ° , r = 100 m , v₂ = 15.0 km / h
a.
To determine v₁ to take a 100 m radius curve banked at 15 °
tan θ = v₁² / r * g
v₁ = √ r * g * tan θ
v₁ = √ 100 m * 9.8 m/s² * tan 15° = 16.2 m/s
b.
To determine μ friction needed for a frightened
v₂ = 15.0 km / h * 1000 m / 1 km * 1h / 60 minute * 1 minute / 60 seg
v₂ = 4.2 m/s
fk = μ * m * g
a₁ = v₁² / r = 16.2 ² / 100 m = 2.63 m/s²
a₂ = v₂² / r = 4.2 ² / 100 m = 0.18 m/s²
F₁ = m * a₁ , F₂ = m * a₂
fk = F₁ - F₂ ⇒ μ * m * g = m * ( a₁ - a₂)
μ * g = a₁ - a₂ ⇒ μ = a₁ - a₂ / g
μ = [ 2.63 m/s² - 0.18 m/s² ] / (9.8 m/s²)
μ = 0.251
Answer: P = 36.75W
The additional power needed to account for the loss is 36.75W.
Explanation:
Given;
Mass of the runner m= 60 kg
Height of the centre of gravity h= 0.5m
Acceleration due to gravity g= 9.8m/s
The potential energy of the body for each step is;
P.E = mgh
P.E = 60 × 9.8 × 0.5
PE = 294J
Since the average loss per compression on the leg is 10%.
Energy loss = 10% (P.E)
E = 10% of 294J
E = 29.4J
To calculate the runner's additional power
given that time per stride is = 0.8s
Power P = Energy/time
P = E/t
P = 29.4J/0.8s
P = 36.75W