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3 years ago

If a car's engine gives off 65% thermal energy, what is the maximum efficiency?

Physics

1 answer:

stich3 [128]3 years ago

5 0

Answer:

35%

Explanation:

The car's engine gives off 65% thermal energy

So only 35 % is converted into mechanical energy .

input heat = Q₁ = 100

output heat = Q₂ = 65

Work output = Q₁ - Q₂ = W

W = 100 - 65 = 35

Efficiency = W / Q₁ X 100

= (35/ 100) X 100

= 35%.

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Importance of electric circuit

Feliz [49]

Answer:

It is important because it carries useful energy through your house that you can use for a variety of tasks.

Explanation:

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3 years ago

20 cubic inches of a gas with an absolute pressure of 5 psi is compressed until its pressure reaches 10 psi. What's the new volu

Anna71 [15]

Answer:

B. $V_{f}= 10\,cubic\,inches$

Explanation:

Assuming we are dealing with a perfect gas, we should use the perfect gas equation:

$PV=nRT$

With T the temperature, V the volume, P the pressure, R the perfect gas constant and n the number of mol, we are going to use the subscripts i for the initial state when the gas has 20 cubic inches of volume and absolute pressure of 5 psi, and final state when the gas reaches 10 psi, so we have two equations:

$P_{i}V_{i}=n_{i}RT_{i}$ (1)

$P_{f}V_{f}=n_{f}RT_{f}$ (2)

Assuming the temperature and the number of moles remain constant (number of moles remain constant if we don't have a leak of gas) we should equate equations (1) and (2) because $T_{i}=T_{f}$ , $n_{i}=n_{f}$ and R is an universal constant:

$P_{i}V_{i}= P_{f}V_{f}$ , solving for $V_{f}$

$V_{f} =\frac{P_{i}V_{i}}{P_{f}} =\frac{(5)(20)}{10}$

$V_{f}= 10 cubic\,inches$

6 0

3 years ago

Can someone pls help with the last one

Leviafan [203]

Answer:

ummmmmmmmmmmm ask your teacher or perant for help

Explanation:

so umm ask an adult or teen figure and maybe you will get it write not sure do

6 0

3 years ago

Sophie throws a tennis ball down from a height of 1.5 m at an angle of 450 with respect to vertical. She drops another tennis ba

Katena32 [7]

Given that,

Height =1.5 m

Angle = 45°

We need to find the greater speed of the ball

Using conservation of energy

$P.E_{i}+K.E_{f}=P.E_{f}+K.E_{f}$

$mgh+\dfrac{1}{2}mv_{i}^2=mgh+\dfrac{1}{2}mv_{f}^2$

Here, initial velocity and final potential energy is zero.

$mgh=\dfrac{1}{2}mv_{f}^2$

Put the value into the formula

$9.8\times1.5=\dfrac{1}{2}v_{f}^2$

$v_{f}^2=2\times9.8\times1.5$

$v_{f}=\sqrt{2\times9.8\times1.5}$

$v_{f}=5.42\ m/s$

Hence, the greater speed of the ball is 5.42 m/s.

5 0

3 years ago

A soap bubble appears red (λ = 633nm) at the point on its front surface nearest to the viewer. Assuming n = 1.35, what is the sm

alexira [117]

Answer:

The smallest film thickness is 117 nm.

Explanation:

Light interference on thin films can be constructive or destructive. Constructive interference is dependent on the film thickness and the refractive index of the medium.

For the first interference (surface nearest to viewer), the minimum thickness can be expressed as:

$2t_{min} = \frac{wavelenth}{2n}$