50km / 2.5 = 20 km per hour
Answer:
A
Explanation:
Momentum is mass times velocity.
A. 275 kg × 0.55 m/s = 151.25 kgm/s
B. 2.7 kg × 7.5 m/s = 20.25 kgm/s
C. 91 kg × 1.4 m/s = 127.4 kgm/s
D. 1.8 kg × 6.7 m/s = 12.06 kgm/s
So A has the greatest momentum.
The answer is B. 11 Hz.
Frequency is always measured in Hertz (Hz), so it can't be C. or D. anyway, but the way to work this out is to do 22 ÷ 2 to work out 11 Hz, because you work out frequency as per second. Also, the formula is f (frequency) = <span>V (velocity) / λ (wavelength). </span>
Answer:
the claim is not valid or reasonable.
Explanation:
In order to test the claim we will find the maximum and actual efficiencies. maximum efficiency of a heat engine can be found as:
η(max) = 1 - T₁/T₂
where,
η(max) = maximum efficiency = ?
T₁ = Sink Temperature = 300 K
T₂ = Source Temperature = 400 K
Therefore,
η(max) = 1 - 300 K/400 K
η(max) = 0.25 = 25%
Now, we calculate the actual frequency of the engine:
η = W/Q
where,
W = Net Work = 250 KJ
Q = Heat Received = 750 KJ
Therefore,
η = 250 KJ/750 KJ
η = 0.333 = 33.3 %
η > η(max)
The actual efficiency of a heat engine can never be greater than its Carnot efficiency or the maximum efficiency.
<u>Therefore, the claim is not valid or reasonable.</u>
Answer:
D
Explanation:
Water in itself is a bad conductor of electricity. Any compound that dissociates in water into ions and charged molecules, will increase conductivity of water. In this case ionic compounds weak basis and acids will put in free ions into the water. The ions can pass electricity because they are attracted to respective poles of electricity depending on their charges. In water, these ions are free moving unlike when they are immobilized in their lattice in solid form.
Organic compounds are mainly made of covalent bonds (around carbon) hence do not dissociate in water.
