Answer:
Convection is the transfer of heat from one place to another along with the motion of the object's particles. Water is a poor conductor. However, when the bottom water is heated, it turns out that the top water is also hot. This means that there is another way of transferring heat to the water, namely convection.
Average speed = (distance traveled) / (time to cover the distance)
= (35 yards) / (3.8 seconds)
= 9.21 yards per second
Answer:
Approximately 18 volts when the magnetic field strength increases from
to
at a constant rate.
Explanation:
By the Faraday's Law of Induction, the EMF
that a changing magnetic flux induces in a coil is:
,
where
is the number of turns in the coil, and
is the rate of change in magnetic flux through this coil.
However, for a coil the magnetic flux
is equal to
,
where
is the magnetic field strength at the coil, and
is the area of the coil perpendicular to the magnetic field.
For this coil, the magnetic field is perpendicular to coil, so
and
. The area of this circular coil is equal to
.
doesn't change, so the rate of change in the magnetic flux
through the coil depends only on the rate of change in the magnetic field strength
. The size of the magnetic field at the instant that
will not matter as long as the rate of change in
is constant.
.
As a result,
.
Answer:

Explanation:
Given:
- work done to stretch the spring,

- length through which the spring is stretched beyond equilibrium,

- additional stretch in the spring length,

<u>We know the work done in stretching the spring is given as:</u>

where:
k = stiffness constant


Now the work done in stretching the spring from equilibrium to (
):



So, the amount of extra work done:



Answer:
Firstly they are, by design, easy to use in most scientific and engineering calculations; you only ever have to consider multiples of 10. If I’m given a measurement of 3.4 kilometres, I can instantly see that it’s 3′400 metres, or 0.0034 Megametres, or 3′400′000 millimetres. It’s not even necessary to use arithmetic, I just have to remember the definitions of the prefixes (“kilo” is a thousand, “megametre” is a million, “milli” is a thousandth) and shift the decimal point across to the left or the right. This is especially useful when we’re considering areas, speeds, energies, or other things that have multiple units; for instance,
1 metre^2 = (1000millimetre)^2 = 1000000 mm^2.
If we were to do an equivalent conversion in Imperial, we would have
1 mile^2 = (1760 yards)^2
and we immediately have to figure out what the square of 1760 is! However, the fact that SI is based on multiples of 10 has the downside that we can’t consider division by 3, 4, 8, or 12 very easily.
Secondly they are (mostly) defined in terms of things that are (or, that we believe to be) fundamental constants. The second is defined by a certain kind of radiation that comes from a caesium atom. The metre is defined in terms of the second and the speed of light. The kelvin is defined in terms of the triple point of water. The mole is the number of atoms in 12 grams of carbon-12. The candela is defined in terms of the light intensity you get from a very specific light source. The ampere is defined using the Lorentz force between two wires. The only exception is the kilogram, which is still defined by the mass of a very specific lump of metal in a vault in France (we’re still working on a good definition for that one).
Thirdly, most of the Imperial and US customary units are defined in terms of SI. Even if you’re not personally using SI, you are probably using equipment that was designed using SI.