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3 years ago

Please help I'll give brainliest!!

Physics

1 answer:

Advocard [28]3 years ago

8 0

Answer:

sound energy is form of mechanical energy.Sound travels as waves of energy, but, unlike light, the waves transmit energy by changing the motion of particles. ... That means that each individual particle is only moving a short distance.

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One and one-half moles of an ideal monatomic gas expand adiabatically, performing 7900 J of work in the process. What is the cha

mart [117]

Answer:

The temperature change is -633.15K

Explanation:

If we considered the expansion as a reversible one (to be adiabatic is one of the requirements), the work done by expansion can be written as:

$W=-n*P(v_2-v_1)=-P*(V_2-V_1)$ Where 2 and 1 subscripts mean the final and the initial state respectively. The equation negative sign says that for an expansion of the gas, the system is making work, so the energy is going out of the system.

Using the ideal gas equation, it is possible to change volume and pressure by temperatures:

$PV_2=(nRT_2)\\PV_1=nRT_1$

So,

$W=-nR(T_2-T_1)$

$(T_2-T_1)=\frac{-W}{nR}=\frac{-7900J}{(1.5mol*8.314\frac{J}{molK})}=-633.5K$

This result makes sense considering that the volume increases, so it is expected that the temperature decreases.

4 0

3 years ago

A projectile is fired at an upward angle of 35.6° from the top of a 208-m-high cliff with a speed of 170-m/s. What will be its s

sdas [7]

Answer:

Final velocity is 181.61 m/s at angle 40.44° below horizontal.

Explanation:

Initial horizontal velocity = 170 cos 35.6 = 138.23 m/s

Final horizontal velocity = 138.23 m/s

Considering vertical motion of projectile:

Initial vertical velocity, u = 170 sin 35.6 = 98.96 m/s

Acceleration, a = -9.81 m/s²

Displacement, s = -208 m

We have v² = u² + 2as

Substituting

v² = 98.96² + 2 x -9.81 x -208

v = 117.79 m/s

Final velocity,

$v=\sqrt{138.23^2+117.79^2}=181.61m/s$

$\theta =tan^{-1}\left ( \frac{117.79}{138.23}\right )=40.44^0$

Final velocity is 181.61 m/s at angle 40.44° below horizontal.

5 0

4 years ago

CORRECT ANSWER WILL BE REWARDED BRAINLIEST

Mandarinka [93]

Answer:

What is 2^-3 x 3^-2 as a fraction?

What is (-2)^-3 x (-3)^-2 as a fraction

Explanation:

I need these pls. SORRYYY

7 0

3 years ago

An above ground swimming pool of 30 ft diameter and 5 ft depth is to be filled from a garden hose (smooth interior) of length 10

STALIN [3.7K]

This question involves the concepts of dynamic pressure, volume flow rate, and flow speed.

It will take "5.1 hours" to fill the pool.

First, we will use the formula for the dynamic pressure to find out the flow speed of water:

$P=\frac{1}{2}\rho v^2\\\\v=\sqrt{\frac{2P}{\rho}}$

where,

v = flow speed = ?

P = Dynamic Pressure = 55 psi $(\frac{6894.76\ Pa}{1\ psi})$ = 379212 Pa

$\rho$ = density of water = 1000 kg/m³

Therefore,

$v=\sqrt{\frac{2(379212\ Pa)}{1000\ kg/m^3}}$

v = 27.54 m/s

Now, we will use the formula for volume flow rate of water coming from the hose to find out the time taken by the pool to be filled:

$\frac{V}{t} = Av\\\\t =\frac{V}{Av}$

where,

t = time to fill the pool = ?

A = Area of the mouth of hose = $\frac{\pi (0.015875\ m)^2}{4}$ = 1.98 x 10⁻⁴ m²

V = Volume of the pool = (Area of pool)(depth of pool) = A(1.524 m)

V = $[\frac{\pi (9.144\ m)^2}{4}][1.524\ m]$ = 100.1 m³

Therefore,

$t = \frac{(100.1\ m^3)}{(1.98\ x\ 10^{-4}\ m^2)(27.54\ m/s)}\\\\$

<u>t = 18353.5 s = 305.9 min = 5.1 hours</u>

Learn more about dynamic pressure here:

brainly.com/question/13155610?referrer=searchResults

7 0

3 years ago

A car is traveling at a velocity of 20 m/s. the driver applies the brakes, and the car slows with an acceleration of a = -4.0 me

sasho [114]

$\displaystyle\\
V = a\times t\\\\
t= \frac{V}{a} = \frac{20}{4} = 5~s\\\\
D = \frac{a\times t^2}{2} = \frac{4\times 5^2}{2} = 2 \times 25 = 50~m$

3 0

3 years ago