Answer:
Given:
Object distance (u) = 25.0 cm
Image distance (v) = -50.0 cm
To Find:
Magnification (m)
Explanation:
Substituting values of Image distance(v) & Object distance (u) in the equation:
-(-50) = 50:
Answer: 2.72 metres
Explanation:
Given that:
frequency of sound F = 123 Hz. wavelength of sound in the air = ?
speed of sound in air V = 334 m/s
Recall that wavelength is the distance covered by the wave after one complete cycle. It is measured in metres, and represented by the symbol λ.
So, apply V = F λ
λ = V /F
λ = 334m/s / 123Hz
λ = 2.72m
Thus, the wavelength of this sound in the air is 2.72 metres
Good work on solving part a).
b) may look complicated, but it's not too bad.
It says that the body is 25% efficient in converting fat to mechanical energy.
In other words, only 25% of the energy we get from our stored fat shows up
in the physical, mechanical moving around that we do. (The rest becomes
heat, which dissipates into the environment as we keep our bodies warm,
breathe hot air out,and perspire.)
You already know how much mechanical energy the climber needed to lift
himself to the top of the mountain... 2.4x10⁶ joules.
That's 25% of what he needs to convert in order to accomplish the climb.
He needs to pull 4 times as much energy out of fat.
-- Fat energy required = 4 x (2.4 x 10⁶) = 9.6 x 10⁶ joules.
-- Amount stored in 1kg of fat = 3.8 x 10⁷ joules
-- Portion of a kilogram he needs to use = (9.6 x 10⁶) / (3.8 x 10⁷)
Note:
That much of a kilogram weighs about 8.9 ounces ... which shows why it's so
hard to lose weight with physical exercise alone. It also helps you appreciate
that fat is much more efficient at storing energy than batteries are ... that one
kilogram of fat stores the amount of energy used by a 100-watt light bulb, to
burn for 105 hours (more than 4-1/2 days ! ! !)
Answer:
t is appropriate to clarify that units such as time and angles the transformation is not in base ten, for example:
60 s = 1 min
60 min = 1 h
24 h = 1 day
Therefore, for this transformation, you must be more careful
the length transformation is base 10
Explanation:
In many exercises the units used are transformed by equations into other units called derivatives, in general the transformation of derived units is the product of the transformation of the constituent units.
In the example of velocity, the derivative unit is m / s, which is why it works in the same way that you transform length and time if in the equation it is multiplying it is multiplied and if it is dividing it is divided.
It is appropriate to clarify that units such as time and angles the transformation is not in base ten, for example:
60 s = 1 min
60 min = 1 h
24 h = 1 day
Therefore, for this transformation, you must be more careful
the length transformation is base 10
1000 m = 1 km
<h2>For Second Solid Lumped System is Applicabe</h2>
Explanation:
Considering heat transfer between two identical hot solid bodies and their environments -
- If the first solid is dropped in a large container filled with water, while the second one is allowed to cool naturally in the air than for second solid, the lumped system analysis more likely to be applicable
- The reason is that a lumped system analysis is more likely to be applicable in the air than in water as the convection heat transfer coefficient so that the Biot number is less than or equal to 0.1 that is much smaller in air
Biot number = the ratio of conduction resistance within the body to convection resistance at the surface of the body
∴ For a lumped system analysis Biot number should be less than 0.1
