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2 years ago

11

A spring whose stiffness is 980 N/m has a relaxed length of 0. 50 m. If the length of the spring changes from 0. 25 m to 0. 81 m

, what is the change in the potential energy of the spring

1 answer:

Gelneren [198K]2 years ago

8 0

151.9j

Explanation:

PE=1/2kx^2

PE=1/2(980)(.50)= 245j

PE=(1/2)(980)(.81)= 396.9j

396.9- 245= 151.9j

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If the intensity level of one trombone is 70 dB, calculate a reasonable estimate for the intensity level of 76 trombones all pla

kogti [31]

Answer:

β₂ = 88.8 dβ

Explanation:

The intensity of the sound is

β = 10 log (I / I₀)

The sensitivity threshold (I₀) for humans is 1 10⁻¹² W / m²

I = I₀ $10^{\beta /10}$

I = 10⁻¹² 10^{70/10}

I = 1 10⁻⁵ W / m²

The total intensity for the 76 trombones is

I_total = n I

I_total = 76 1 10⁻⁵

I_total = 76 10⁻⁵ W / m²

Let's find the sound level

β₂ = 10 log (76 10⁻⁵ / 10⁻¹²)

β₂ = 88.8 dβ

8 0

3 years ago

Problem 6.056 Air enters a compressor operating at steady state at 15 lbf/in.2, 80°F and exits at 275°F. Stray heat transfer and

vova2212 [387]

To solve this process it is necessary to consider the concepts related to the relations between pressure and temperature in an adiabatic process.

By definition the relationship between pressure and temperature is given by

$(\frac{P_2}{P_1})=(\frac{T_2}{T_1})^{(\frac{\gamma}{\gamma-1})}$

Here

P = Pressure

T = Temperature

$\gamma =$ The ratio of specific heats. For air normally is 1.4.

Our values are given as,

$P_1 = 15lb/in^2\\T_1= 80\°F = 299.817K\\T_2 =400\°F = 408.15K$

Therefore replacing we have,

$(\frac{P_2}{P_1})=(\frac{T_2}{T_1})^{(\frac{\gamma}{\gamma-1})}$

$(\frac{P_2}{15})=(\frac{408.15}{299.817})^{(\frac{1.4}{1.4-1})}$

Solving for $P_2,$

$P_2 = 15*(\frac{408.15}{299.817})^{(\frac{1.4}{1.4-1})}$

$P_2 = 44.15Lbf/in^2$

Therefore the maximum theoretical pressure at the exit is $44.15Lbf/in^2$

5 0

3 years ago

crowbar of 5 metre is used to lift an object of 800 metre if the effort arm is 200cm calculate the force applied

Klio2033 [76]

Answer:

F = 5226.6 N

Explanation:

To solve a lever, the rotational equilibrium relation must be used.

We place the reference system on the fulcrum (pivot point) and assume that the positive direction is counterclockwise

F d₁ = W d₂

where F is the applied force, W is the weight to be lifted, d₁ and d₂ are the distances from the fulcrum.

In this case the length of the lever is L = 5m, t the distance desired by the fulcrum from the weight to be lifted is

d₂ = 200 cm = 2 m

therefore the distance to the applied force is

d₁ = L -d₂

d₁ = 5 -2

d₁= 3m

we clear from the equation

F = W d₂ / d₁

W = m g

F = m g d₂ / d₁

we calculate

F = 800 9.8 2/3

F = 5226.6 N

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3 years ago

Please help!!................

Gnoma [55]

D. When a substance reacts with another substance, it shows its chemical property

3 0

3 years ago

A planned high-speed train between Houston and Dallas will travel a distance of 386 kilometers in 5.40 × 10^3 seconds. What is t

Mazyrski [523]

¡Hellow!

For this problem, first, lets convert the seconds in hours:

5,4x10³ $\rightarrow$ 5400

h = sec / 3600

h = 5400 s / 3600

h = 1,5

Let's recabe information:

d (Distance) = 386 km

t (Time) = 1,5 h

v (Velocity) = ?

For calculate velocity, let's applicate formula:

$\boxed{\boxed{\textbf{d = v * t} } }$

Reeplace according we information:

386 km = v * 1,5 h

v = 386 km / 1,5 h

v = 257,33 km/h

The velocity of the train is of <u>257,33 kilometers for hour.</u>

<u></u>

Extra:

For convert km/h to m/s, we divide the velocity of km/h for 3,6:

m/s = km/h / 3,6

Let's reeplace:

m/s = 257,33 km/h / 3,6

m/s = 71,48

¿Good Luck?

7 0

3 years ago