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:
The correct answer is option A, An antacid neutralizes excess hydrogen ions.
Explanation:
Antacid neutralizes the acid in the stomach. These are bases/ alkali's. The reaction between an acid and a base in known as neutralization thereby reducing burning sensations produced by the acid.
The antacid when reaches the stomach form gel like composition that lie on the top of food item in the stomach and prevent the oesophagus from the irritation caused by the acid.
Answer:
All the given option is false.
Explanation:
A)
This is not true for all the materials like composite because the Poisson ratio for composite material can be negative that is why positive tensile stress may produce positive lateral strain.
B)
This is not true for all the material because the Poisson ratio for some material can be positive that is why positive tensile stress may produce negative lateral strain.
C)
The explanation is same as option A.
D)
This is not true for all the materials ,It is valid only up to elastic limit .After the elastic limit the strain and stress does not follow linear path.
E)
This is not true for all the materials because some materials like composite is having negative value of Young's modulus.
Therefore all the given option is false.
Answer:
Contour line, a line on a map representing an imaginary line on the land surface, all points of which are at the same elevation above a datum plane, usually mean sea level. The diagram illustrates how contour lines show relief by joining points of equal elevation. Encyclopædia Britannica, Inc. Video Player is loading.
