In what way are all sounds alike?

2. A person lifts 200kg seven times over the course of 11.8s. If they displaced the weight 2.2m up each time, how much power did

Aneli [31]

Answer:

<em>The person delivered a power of 2,558 Watt</em>

Explanation:

<u>Work and Power</u>

Mechanical work is the amount of energy transferred by a force. It's a scalar quantity, with SI units of joules.

Being the force vector and the displacement vector, the work is calculated as:

$W=\vec F\cdot \vec s$

If both the force and displacement are parallel, then we can use the equivalent scalar formula:

W=F.s

Power is the amount of energy transferred per unit of time. In the SI, the unit of power is the watt, equivalent to one joule per second.

The power can be calculated as:

$\displaystyle P=\frac {W}{t}$

Where W is the work and t is the time.

If the person lifts a mass of m=200 Kg, then exerts a force equal to its weight:

F = m.g = 200*9.8 = 1,960

F = 1,960 N

The work done when lifting the weight 7 times by a distance of s=2.2 m is:

W = 7*1,960*2.2=30,184

W = 30,184 J

Finally, the power delivered in t=11.8 seconds is:

$\displaystyle P=\frac {30,184}{11.8}$

P = 2,558 Watt

The person delivered a power of 2,558 Watt

4 0

3 years ago

A bubble, located 0.200 m beneath the surface in a glass of beer, rises to the top. The air pressure at the top is 1.01x10⁵ Pa.

Cerrena [4.2K]

Answer:

$\frac{1.019}{1}$

Explanation:

To solve this equation we will have to consider that the bubble is filled with an Ideal Gas and as such we can use the Ideal Gas Law

$PV = nRT$

Where

$P$ = Pressure

$V$ = Volume

$n$ = Moles

$R$ = Ideal Gas Constant

$T$ = Temperature

Now since we know that the value for the temperature and moles is constant we can simply use Boyles Law for the two states

$P_{1} V_{1} =P_{2} V_{2}$

Let us look at the two states

State 1 (at top)

Pressure = $1.01*10^5$

Volume = $V_{1}$

State 2 (at bottom)

Pressure = $1.01*10^5 + dgh$

Where

$d$ = Density of liquid (1000 kg/m³)

$d$ = Acceleration due to gravity (9.8 m/s²)

$d$ = Height of liquid (0.200 m)

Pressure = $102,962$

Volume = $V_{2}$

Inputting these values into the Boyles Law

$P_{1} V_{1} =P_{2} V_{2}\\ (101000)V_{1} = (102962)V_{2}\\ \frac{V_{1}}{V_{2}} = \frac{102962}{101000} \\ \frac{V_{1}}{V_{2}} = \frac{1.019}{1}$

6 0

3 years ago

A train travels 99 kilometers in 2 hours, and then 90 kilometers in 3 hours. What is its average speed?

Agata [3.3K]

Average speed =

(total distance)/(total time)

Average speed = (99+90)/(2+3)

That's (189 km) / (5 hr)

Average speed = 37.8 km/hr

3 0

3 years ago

The area of the bar over r = 2 is 0.234. what is the area of the bar over r = 4?

natita [175]

The area of the bar over r=4 is 0.468

4 0

3 years ago

A batter hits a pop fly, and the baseball (with a mass of 148 g) reaches an altitude of 265 ft. If we assume that the ball was 3

den301095 [7]

Answer:

The increase in potential energy of the ball is 115.82 J

Explanation:

Conceptual analysis

Potential Energy (U) is the energy of a body located at a certain height (h) above the ground and is calculated as follows:

U = m × g × h

U: Potential Energy in Joules (J)

m: mass in kg

g: acceleration due to gravity in m/s²

h: height in m

Equivalences

1 kg = 1000 g

1 ft = 0.3048 m

1 N = 1 (kg×m)/s²

1 J = N × m

Known data

$h_2 = 265ft * \frac{0.3048m}{ft} = 80.77m$

$h_1 = 3ft * \frac{0.3048m}{ft} = 0.914m$

$m = 148g*\frac{1kg}{1000g} = 0.148kg$

$g = 9.8 \frac{m}{s^2}$

Problem development

ΔU: Potential energy change

ΔU = U₂ - U₁

U₂ - U₁ = mₓgₓh₂ - mₓgₓh₁

U₂ - U₁ = mₓg(h₂ - h₁)

$U_2 - U_1 = 0.148kg * 9.8 \frac{m}{s^2}*(80.77m - 0.914m) = 115.82 N * m = 115.82J$

The increase in potential energy of the ball is 115.82 J

5 0

3 years ago