what is the efficiency of an engine that dies 288 J of work and exhausts 72 J of heat while taking 360 J of heat?

Answer:

Explanation:

The equation for work is

W = FΔx

We are looking for work, so that means we have to be able to fill in the Force and the displacement. We have Force, but we don't have displacement. But the thing we need to do first is change the 45 minutes to seconds because the velocity is in m/s, not m/min.

45 minutes is 2700 seconds.

That means that  the displacement is

Δx = (.90)(2700) so

Δx = 2430 m

Now we plug that in to find work, along with the given Force:

W = 40(2430) so

W = 97200 J (and that is not the correct number of sig fig's but I have a feeling you're not too into that in class, because if you were, the 40 N would be expressed as 40.0 or 4.0 × 10¹)

If the car's motion appears as a horizontal line on a position-time graph, it shows that as time changes, the car's position doesn't change.

This is just a complicated way to say that the car is not moving. (A)

Answer: It's not moving.

Explanation:

I got it correct on edmentum.

Answer:

the brightest found are Blue - White with

Explanation:

The energy emission of objects increases with their temperature, specifically Wien described the process in an expression

          [tex]\lambda_{maximum}[/tex] T = 2,898 10⁻³

With this expression we can find the temperature of the stars by the color they emit.

Specifically the Sun has a color of 550 nm which corresponds to 5400K

bright stars have a BLUE color corresponding to 7500K

the brightest found are Blue - White with a temperature of 20000K

Complete question is;

A bicycle and a car start their journey at the same time the cyclist reaches it's top speed of 10m/s in 15 s, the car reaches a speed of 15 m/s in 55 s. which has the greater acceleration the car or the bicycle.

Answer:

The bicycle has the greater acceleration.

Explanation:

Cyclist reaches a top speed of 10m/s in 15 s.

Formula for acceleration here is;

a = v/t

a = 10/15

a = 0.67 m/s²

Car reaches a speed of 15 m/s in 55 s.

Thus;

a = 15/55

a = 0.27 m/s²

From the 2 acceleration values gotten, we can say that;

The bicycle has the greater acceleration.

Answer:

50 km/h

Explanation:

[tex](40 + 60) / 2[/tex]

-> [tex]50[/tex] (km/h)

Answer:

(a) t = 0.75 s

(b) d = 26 m

Explanation:

Height, h = 12 m

Angle, A = 30 degree

initial velocity, u = 40 m/s

(a) Let the time is t.

Use second equation of motion

 [tex]h = u t + 0.5 at^2\\\\12 = 40 sin 30 t - 0.5 \times10 \times t^2\\\\12 = 20 t - 5 t^2\\\\5 t^2 - 20 t + 12 =0 \\\\t = \frac{20\pm \sqrt{400-240}}{10}\\\\t = \frac{20\pm 12.65}{10}\\\\t = 3.3 s, 0.75 s[/tex]

(b) d = u cos A t

d = 40 x cos 30 x 0.75 = 26 m

Answer:

im pretty sure it should be 50.0

Answer:

Explanation:

The cell is acting like a shell .

Capacity of a shell is given by the following expression.

C= 4πk ε₀ x ab / (b-a )

k is dielectric constant , b and a are outer and inner radius ε₀ is a constant .

Here a = 2.3 x 10⁻⁶ m

b = 2.3 x 10⁻⁶ + .00375 x 10⁻⁶

= 2.30375 x 10⁻⁶ m

b -a = 3.75 x 10⁻⁹ m .

k = 9

4π ε₀ = 1 / 9 x 10⁹ = .111 x 10⁻⁹

C=  .111 x 10⁻⁹ x 9 x 2.3 x 10⁻⁶ x 2.30375 x 10⁻⁶ / 3.75 x 10⁻⁹

= 1.41 x 10⁻¹² F

= 1.41 pF .

Answer:

519.62 m/s

Explanation:

Applying,

v = √(T/m').............. Equation 1

Where v = velocity of the wave, T = Tension on the string, m' = mass per unit length of the string

From the question,

Given: T = 1350 N, m' = 0.005 kg/m

Substitute these values into equation 1

v = √(1350/0.005)

v = √(270000)

v = 519.62 m/s

Answer:

The fraction of the protons would have no electrons [tex]=1.88\times 10^{-10}[/tex]

Explanation:

We are given that

Amoeba has total number of protons=[tex]1.00\times 10^{16}[/tex]

Net charge, Q=0.300pC

Electrons are fewer than protons=[tex]1.88\times 10^6[/tex]

We have to find the fraction of protons would have no electrons.

The fraction of the protons would have no electrons

=[tex]\frac{Fewer\;electrons}{Total\;protons}[/tex]

The fraction of the protons would have no electrons

=[tex]\frac{1.88\times 10^{6}}{1.00\times 10^{16}}[/tex]

[tex]=1.88\times 10^{-10}[/tex]

Hence, the fraction of the protons would have no electrons [tex]=1.88\times 10^{-10}[/tex]

Answer:

An object overall change in position

Explanation:

ans maybe corre6

Answer:

     U = 3.59 10⁻⁹ J

Explanation:

Electric potential energy is

             U = k ∑ [tex]\frac{q_iq_j }{r_i_j}[/tex]

in this case

            U = k (q₁q₂ / r₁₂ + q₁q₃ / r₁₃ + q₂q₃ / r₂₃)

the distances are

            r₁₂ = 1.15

            r₁₃ = 1.15 +2.88 = 4.03 m

            r₂₃23 = 2.88

we substitute

            U = 9 109 (2 10-5 3.8 10-6 / 1.15 + 2 10-5 5.30 10-5 / 4.03 + 3.8010-6 53 010-5 / 2.88)

             U = 9 109 (6.609 10-11 + 2.63 10-10 + 6.99 10-11)

            U = 9 109 (39,899 10-11)

            U = 3.59 10⁻⁹ J

Answer:

Q2 = 0.0346 J

Explanation:

I don't know what Q1 is but I did solve for Q2. I'm using this because no other question has been asked to solve for Q2 :)

Answer:

b and d

Explanation:

Answer:

True

Explanation:

Speed = distance/time

If distance and time are the same, then the right hand side of the equation remains the same, causing us to solve the left to the same value

As the distance is the same (say 50m) and the time is the same (say 50s) then the speed must be the same (1m/s)

Answer: 0.5 m

Explanation:

Given

Mass of the person is [tex]m=50\ kg[/tex]

Trampoline launches the person into the air up to height of [tex]h=2\ m[/tex]

Force experience by springs is [tex]F=1960\ N[/tex]

Here, the work done on displacing the springs is equivalent to the Potential energy acquired by the person i.e.

[tex]\Rightarrow F\cdot x=mgh\quad [\text{x=displacement of the trampoline}]\\\\\text{Insert the values}\\\\\Rightarrow x=\dfrac{50\times 9.8\times 2}{1960}\\\\\Rightarrow x=\dfrac{980}{1960}\\\\\Rightarrow x=0.5\ m[/tex]

Answer:

0.5

Explanation:

Answer:

Mass = 64,870,000,000 kilograms

Explanation:

Given the following data;

Density = 998 kg/m³

Volume = 6,500,000 m³

To find the mass of water in the reservoir;

Density can be defined as mass all over the volume of an object.

Simply stated, density is mass per unit volume of an object.

Mathematically, density is given by the equation;

Density = mass/volume

Making mass the subject of formula, we have;

Mass = density * volume

Mass = 998 * 6,500,000

Mass = 64,870,000,000 kilograms

Answer:

Distancia, S = 136 metros

Explanation:

Dados los siguientes datos;

Aceleración, a = 3 m/s²

Velocidad inicial, u = 5 m/s

Tiempo, t = 8 segundos

Para encontrar la distancia recorrida, usaríamos la segunda ecuación de movimiento;

S = ut + ½at² Sustituyendo en la fórmula, tenemos;

S = 5 × 8 + ½ × 3 × 8²

S = 40 + 1,5 × 64

S = 40 + 96

Distancia, S = 136 metros

Answer:

A positively charged object moving due west in a region where the Earth's magnetic field is due north experiences a force that is straight down as shown.

A negative charge moving in the same direction would feel a force straight up.

Answer:

what if I do and b then someone else c I don't have enough time pls

Answer:

1-The liquid pressure is same at all points lying on the same horizontal plane in a stationary liquid.

2-The liquid pressure at a point inside the liquid is same in all directions.

3-The liquid pressure at a point inside the liquid is directly proportional to the depth of that point from the free surface of liquid.

4-The pressure of liquid at same depth is different for different liquids. It is directly proportional to density of liquid. That is, for same depth the liquid pressure is larger for liquid of larger density.

Explanation:

Explanation:

Noise is sound with a continuous structure. Music is composed of sounds with a fundamental frequency and overtones. Noise is composed of sounds with frequencies that range continuously in value from as low as you can hear to as high as you can hear — not necessarily at equal intensity, however.

Answer:

The total displacement of the car is 250 km.

Explanation:

Given that,

A car at a position 150 km [W] of Toronto travels to a position 400 km [W] of  Toronto.

Total displacement = final position - initial position

= 400 km - 150 km

= 250 km

So, the total displacement of the car is 250 km.

Answer:

may be upside down alphabet :"T"

Explanation:

Answer:

39 m/s²

Explanation:

initial Velocity (u) = 9m/s

acceleration (a) = 1.5m/s²

time(t) = 20s

V=u + at

V=9 + 1.5(20)

V=9 + 30

V=39m/s

Answer:

Explanation:

Newton's law of gravitation states that every particle of matter attracts any other particle in the universe with a force directly proportional to the product of there masses and inversely proportional to the square of the distance between them.

This law is also called universal law because it is applicable to all masses at all distances irrespective of the medium.

Answer:

Explanation:

The PE equation for a mass/spring system is

[tex]PE=\frac{1}{2}k[/tex]Δx² and filling in:

[tex]130=\frac{1}{2}k(.10)^2[/tex] and

[tex]k=\frac{2(130)}{(.10)^2}[/tex] so

k = 26000 N/m

If the displacement from equilibrium changes more, the PE needed to compress it will also change.

[tex]PE=\frac{1}{2}(26000)(.20)^2[/tex] gives us that

PE = 520J

Answer:

b. they move in convection currents.

Explanation:

i learned this in 4th grade

Answer:

150 kJ

Explanation:

Applying,

ΔH = Energy level of Product(E') - Energy level of reactant(E)

Where ΔH = enthalpy change, E' and E = energy level of the product and the reactant respectively

ΔH = E'-E............. Equation 1

From the diagram,

Given: E' = 200 kJ, E = 50 kJ

Substitute these values into equation 1

ΔH = 200-50

ΔH = 150 kJ

Hence the enthalpy change for the reaction is 150 kJ

The drawing shows the couple acting on a tire wrench is missing and so i have attached it.

We are to find an expression for the torque when the axis is perpendicular to the tire and passes through the points A, B & C

Answer:

Point A: τ = Fl

Point B: τ = 0

Point C: - Fl

Explanation:

Formula for torque is;

τ = F × d

Where;

F is perpendicular force

d is distance.

Thus;

> At point A, it means we are taking torque about point A and so we have;

τ = (-F × 0) + (F × L)

τ = Fl

> At point B, it means we are taking torque about point B and so we have;

τ = (-F × L/2) + (F × L/2)

τ = -(FL/2) + (FL/2)

τ = 0

> At point C, it means we are taking torque about point C and so we have;

τ = (-F × L) + (F × 0)

τ = -FL