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3 years ago

Describe why cars are inefficient machines in terms of thermodynamics.

2 answers:

8 0

Cars are inefficient by the fact that they convert fuel (chemical energy) to mechanical energy, only 30-40% of that energy can be converted to move the car.

Since Thermodynamic is basically about the conversion of energy, cars are inefficient since something has to be able to convert at least 50-75% of the energy to be efficient.

Alina [70]3 years ago

6 0

Cars are the mechanical device which convert chemical energy of fuel into mechanical energy, the engine used in the automobiles car are very inefficient, they can only convert 30-40% of chemical energy of fuel into mechanical energy, since thermodynamics is the branch of science that deals with the conversion of energy, thus due to poor conversion rate of chemical energy into mechanical energy, cars are known as inefficient machine.

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A coil of wire contains N turns and has an electrical resistance R. The radius of each turn is a. Initially, inside the coil the

GuDViN [60]

Answer:

Using Faraday's law;

ε= -N ∆ψ(B)/ ∆t;

∆t= -N ∆ψ(B)/ ε

Explanation:

Using Faraday's law; Faraday's law state that the induced emf is directly proportional to the rate of change of time of magnetic flux

ε= -N ∆ψ(B)/ ∆t;

Where ε= induced EMF, ∆ψ(B)/ ∆t is the rate of change of magnetic flux, ψ(B) = BA cos θ

θ= the angle between the magnetic field B and the normal surface area.

We can also calculate the direction of induced magnetic flux. At first, the field is perpendicular to the plane of the loop,the loop can rotate about either an horizontal or vertical axis passing through the mid point

5 0

3 years ago

Which has more calories Donuts or Apples?

anyanavicka [17]

Donut

$\: \: \: \:$

3 0

3 years ago

Water is drawn from a well in a bucket tied to the end of a rope whose other end wraps around a solid cylinder of mass 50 kg and

sleet_krkn [62]

Answer:

$\alpha=78.4\ rad.s^{-2}$

Explanation:

Given:

mass of solid cylinder, $m=50\ kg$

diameter of cylinder, $d=0.25\ m$

mass of bucket of water, $m_w=20\ kg$

<em>When the bucket is released to fall in the well, it fall under the acceleration due to gravity.</em>

We have formula for angular acceleration as:

$\alpha=\frac{g}{r}$

where:

g = acceleration due to gravity

r = radius of the cylinder

$\aplha=\frac{9.8}{0.125}$

$\alpha=78.4\ rad.s^{-2}$

4 0

3 years ago

A common practice in cooking is the addition of salt to boiling water (Kb = 0.52 °C kg/mole). One of the reasons for this might

lozanna [386]

Answer:

640.59 g of NaCl.

Explanation:

Using Boiling point elevation,

ΔTb = kb * i * b

Where,

b = molality

kb = 0.52 °C kg/mole

i = van't koff factor

ΔTb = ΔTsol - ΔTsolv

= 2°C

2 = 0.52 * b

= 3.846 mol/kg.

Mass of water, solvent = 2.85 kg

Molality is the ratio of the number of moles of the solute to the mass of the solvent.

= 3.846 * 2.85

= 10.96 mol.

Mass of NaCl = molar mass * number of moles

= 58.44 * 10.96

= 640.59 g of NaCl.

5 0

3 years ago

Which of the following is the condition that exists when the frequency of the force applied to a system matches the natural freq

Tpy6a [65]

Answer:

Mechanical resonance is the tendency of a mechanical system to respond at greater amplitude when the frequency of its oscillations matches the system's natural frequency of vibration (its resonance frequency.

Explanation:

3 0

4 years ago