Answer:
The mass of the 500 series bullet train is 181.4 tonnes.
Explanation:
The momentum is given by:

Where:
m: is the mass =?
v: is the velocity = 261.8 km/h
p: is the momentum = 13194098.64 kg*m/s
By solving the above equation for "m" we have:

Therefore, the mass of the 500 series bullet train is 181.4 tonnes.
I hope it helps you!
Answer : The correct option is, (D) A machine does 400 joules of work in 5 seconds.
Explanation :
Power : It is defined a the rate of doing work per unit time.
Formula used :

where,
P = power
w = work done
t = time
Now we have to determine the rate of power for the following options.
(A) A machine does 200 joules of work in 10 seconds.

(B) A machine does 400 joules of work in 10 seconds.

(C) A machine does 200 joules of work in 5 seconds.

(D) A machine does 400 joules of work in 5 seconds.

From this we conclude that, a machine does 400 joules of work in 5 seconds has the highest rate of power.
Hence, the correct option is, (D)
Answer:
B. The elastic portion of a straight-line, downward-sloping demand curve corresponds to the segment above the midpoint.
Explanation:
Elasticity measures the sensitivity of one variable to another. Specifically it is a figure that indicates the percentage variation that a variable will experience in response to a variation of another one percent.
The elasticity of demand measures the reaction of demand when one of the factors that affects it varies.
<u>Elasticity - Price of demand.</u>
easure the sensitivity of the quantity demanded to price variations. It indicates the percentage variation that the quantity demanded of a good will experience if its price rises by 1 percent.
<u>
Elastic Demand
</u>
The demand quantity is relatively sensitive to price variations, so the total expenditure on the product decreases when the price rises, the price elasticity takes value greater than -∞ but less than -1
<span>haha I used to think biology was so hard, i find it quite easy now.
Okay, so basically Osmosis is the movement of water molecules from a higher concentration to a lower concentration. Diffusion is generally the movement of a gradient from higher concentration to an area of lower concentration. Osmosis applies to water only, whereas diffusion, you have many types such as Passive transport [ movement of molecules from high- low, NO CELLULAR ENERGY needed! ] then you have faciliated diffusion ( basically uses a channel protein to allow big substances to go through the membrane : NO ENERGY needed]
OSMOSIS, the important thing to remember is that water ALWAYS flow towards the region with the higher concentration of the solute (ex: Salt is solute, water is solvent) solute is the thing that is being dissolved. Solvent is the one doing the dissolving. Hope this helped!</span>
Answer:
Chemical composition, Temperature, Radial velocity, Size or diameter of the star, Rotation.
Explanation:
Elemental abundances are determined by analyzing the relative strengths of the absorption lines in the spectrum of a star.
The Spectral class to which the star belongs gives the information related to the temperature of the star. It is the spectral lines that determine the spectral class O B A F G K M are the spectral classes.
By measuring the wavelengths of the lines in the star's spectrum gives the radial velocity. Doppler shift is the method used to find the radial velocity.
A star can be classified as a giant or a dwarf . A giant star will have narrow width spectral lines whereas a dwarf star has wider spectral lines.
Broadening of the spectral lines will determine the star's rotation.