Solve the compound inequality. 3x − 4

One AA battery in a flashlight stores 9400 J. The three LED flashlight bulbs consume 0.5 W. How many hours will the flashlight l

Effectus [21]

Answer:

time = 5.22 hr

Explanation:

Given data:

Energy of battery = 9400 J

Power consumed by three led bulb is 0.5 watt

we know Power is give as

$Power = \frac{ energy}{time}$

plugging all value and solve for time

$time = \frac{energy}{power}$

$time = \frac{9400}{0.5}$

time = 18,800 sec

in hour

1 hour = 3600 sec

therefore in 18,800 sec

$time = \frac{18800}{3600} = 5.22 hr$

7 0

3 years ago

Water flows in a tube that has a diameter of D= 0.1 m. Determine the Reynolds number if the average velocity is 10 diameters per

Cloud [144]

Answer:

a) $Re_{D} = 111896.745$ , b) $Re_{D} = 1.119\times 10^{-7}$

Explanation:

a) The Reynolds number for the water flowing in a circular tube is:

$Re_{D} = \frac{\rho\cdot v\cdot D}{\mu}$

Let assume that density and dynamic viscosity at 25 °C are $997\,\frac{kg}{m^{3}}$ $0.891\times 10^{-3}\,\frac{kg}{m\cdot s}$ , respectively. Then:

$Re_{D}=\frac{(997\,\frac{kg}{m^{3}} )\cdot (1\,\frac{m}{s} )\cdot (0.1\,m)}{0.891\times 10^{-3}\,\frac{kg}{m\cdot s} }$

$Re_{D} = 111896.745$

b) The result is:

$Re_{D}=\frac{(997\,\frac{kg}{m^{3}} )\cdot (10^{-6}\,\frac{m}{s} )\cdot (10^{-7}\,m)}{0.891\times 10^{-3}\,\frac{kg}{m\cdot s} }$

$Re_{D} = 1.119\times 10^{-7}$

6 0

3 years ago

In a vehicle with front disc brakes, the vehicle pulls to the left when braking. What causes this?

IrinaVladis [17]

The answer to your question is A

3 0

2 years ago

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Suppose you want to find the sum of two sinusoidal voltages, given as follows: v1(t)=V1 cos(ωt+ϕ1) and v2(t)=V2 cos(ωt+ϕ2)v1(t)=

seropon [69]

Answer:

Attached is the full solution.

3 0

2 years ago

Read 2 more answers

A heating element in a stove is designed to receive 4,430 W when connected to 240 V. (a) Assuming the resistance is constant, ca

kiruha [24]

Answer:

a) The current in the heating element when it is connected to 120 V is 9.229 amperes, b) The power received by the heatng element connected to 120 V is 1107.522 watts.

Explanation:

a) The resistance as a function of voltage and power can be obtained from this expression, derived from the Ohm's Law:

$\dot W = \frac{V^{2}}{R}$

Where:

$V$ - Source voltage, measured in volts.

$R$ - Heating element resistance, measured in ohms.

Now, resistance is clear and determined afterwards:

$R = \frac{V^{2}}{\dot W}$

If $V = 240\,V$ and $\dot W = 4,430\,W$ , then:

$R = \frac{(240\,V)^{2}}{4.430\,W}$

$R = 13.002\,\Omega$

Now, let consider that heating element is conected to a 120-V source. The power generated by this element is:

$\dot W = \frac{V^{2}}{R}$

$\dot W = \frac{(120\,V)^{2}}{13.002\,\Omega}$

$\dot W = 1107.522\,W$

Besides, power as a function of current and resistance is given by this:

$\dot W = i^{2}\cdot R$

Where $i$ is the current required by the heating element, measured in amperes, and which is cleared herein:

$i = \sqrt{\frac{\dot W}{R} }$

If $\dot W = 1107.522\,W$ and $R = 13.002\,\Omega$ , then:

$i = \sqrt{\frac{1107.522\,W}{13.002\,\Omega} }$

$i \approx 9.229\,A$

The current in the heating element when it is connected to 120 V is 9.229 amperes.

b) The power received by the heatng element connected to 120 V is 1107.522 watts. (see point a) for further details)

6 0

3 years ago

Solve the compound inequality. 3x − 4 > 5 or 1 − 2x ≥ 7