Answer:
a. 120 W
b. 28.8 N
Explanation:
To a good approximate, the only external force that does work on a cyclist moving on level ground is the force of air resistance. Suppose a cyclist is traveling at 15 km/h on level ground. Assume he is using 480 W of metabolic power.
a. Estimate the amount of power he uses for forward motion.
b. How much force must he exert to overcome the force of air resistance?
(a)
He is 25% efficient, therefore the cyclist will be expending 25% of his power to drive the bicycle forward
Power = efficiency X metabolic power
= 0.25 X 480
= 120 W
(b)
power if force times the velocity
P = Fv
convert 15 km/h to m/s
v = 15 kmph = 4.166 m/s
F = P/v
= 120/4.166
= 28.8 N
definition of terms
power is the rate at which work is done
force is that which changes a body's state of rest or uniform motion in a straight line
velocity is the change in displacement per unit time.
Answer:
T=273+25=298 K
n= m/M = 10/ 4 = 2.5
R=0.08206 L.atm /mol/k
760mmHg = 1 atm therefore
600mmHg = X atm
760 X = 600mmHg
X = 600/760 = 0.789 atm
P = 0.789 atm
V= ?
PV= nRT
0.789 V = 2.5 × 0.08206 × 298
V= 2.5 × 0.08206 ×298 / 0.789
V= 77.48 L
I hope I helped you ^_^
Answer:
4 m/s
Explanation:
From the question given above, the following data were obtained:
Maximum range (Rₘₐₓ) = 1.6 m
Acceleration due to gravity (g) = 10 m/s²
Initial velocity (u) =?
The initial velocity of the projectile can be obtained as follow:
Rₘₐₓ = u² / g
1.6 = u² / 10
Cross multiply
u² = 1.6 × 10
u² = 16
Take the square root of both side
u = √16
u = 4 m/s
Therefore, the velocity of the projectile is 4 m/s
I am fairly certain it's D. Good luck!
Answer:
7.35m/s
Explanation:
Kinetic energy = 1/2 MV^2
From the question
Kinetic energy = 6.8x10^3J
Mass = 225kg
V =?
Using the above formula
We have
6.8x10^3 = 1/2 x 225 x v^2
6.8x10^3 = 112.5 x v^2
Divide both sides by 112.5
We have
6.8x10^3 / 112.5 = v^2
v ^2 = 54.04
V = squared root of 54.04
v = 7.35m/s
