A 2000 kg car is traveling at 10 m/s, and then it slows to 5 m/s. How much work is done on the car by the brakes and friction?

There is evidence that elephants communicate via infrasound, generating rumbling vocalizations as low as 14 Hz that can travel u

amid [387]

Answer:

$L = 96.2 dB$

Explanation:

As we know that the level of intensity is given as

$\beta = 10Log(\frac{I}{I_o})$

here we know

$\beta = 104 dB$

$104 = 10Log(\frac{I}{10^{-12}})$

$I = 0.025 W/m^2$

now the sound is travelling in all possible directions so we have

$\frac{I_1}{I_2} = \frac{r_2^2}{r_1^2}$

$\frac{0.025}{I_2} = \frac{10^2}{4.1^2}$

$I_2 = 4.2 \times 10^{-3} W/m^2$

now for level of sound we have

$L = 10Log(\frac{4.2 \times 10^{-3}}{10^{-12}})$

$L = 96.2 dB$

5 0

3 years ago

it takes 1.4 minutes for Jonny to get to class which is a distance of 82 meters away s. what is Johnny’s average speed in second

Marat540 [252]

We have to use the equation speed=distance/time.
We want the average speed in second so we have to change the minutes into seconds. We can do this by multiplying the minutes by 60 (60seconds in 1 minute). 60x1.4= 84 seconds.
Speed=distance/time, distance is 82 and time is 84 so speed=82/84
Average speed = 0.98ms^-1 (2dp)

4 0

4 years ago

At this output power, how long would it take an 89 kg cyclist (including the mass of his bike) to climb the famed 1100-m-high al

Artemon [7]

<span>In general the route that follows the 1100-m-high alpe d'huez mountain stage takes anywhere from four to six hours in athletes from around the world. A beginner would probably take 8 hours or so. World records were recently broken with a time just under three hours. The most friction for cyclist is the competition itself.</span>

7 0

3 years ago

A satellite in a nearly circular orbit is 2000 km above earth's surface. the radius of earth is approximately 6400 km. if the sa

Ann [662]

Velocity is computed using the formula:

$v= \frac{d}{t}$
Where:
V = speed
d = distance traveled
t = time/period

First you need to consider that the orbit is circular. To get the measurement or the distance going around Earth, you will need to get the circumference of the path.

$C = 2 \pi r$

Where:
C = circumference
π = 3.14
r = radius

The Earth has a radius of 6,400km, but you also need to consider that the satellite is orbiting above the surface of the Earth, so you add in the 2,000km to that radius.

r = 6,400Km + 2,000Km = 8,400Km

Next step is to insert that into our circumference formula:

$C = 2 \pi r$
$C = 2 \pi 8,400Km$
$C = 52,778.76 Km$

The distance traveled would then be 52,778.76Km

Now that we have the distance, we can then get the velocity:

$v= \frac{d}{t}$
$v= \frac{52,778.76Km}{12hrs}$
$v= 4,398.23km/hr$

The speed of the satellite is 4,398.23km/hr.

7 0

3 years ago

A television has a mass of 19kg what is the weight of the television

satela [25.4K]

Answer:

186 N

ExplanatioN

Weight is essentially just a measurement of the force of gravity, so you can use this equation.

F = mg

Force = Mass × Acceleration due to Gravity

F = 19kg × 9.8m/s^2. (Acceleration due to Gravity on Earth.)

F = 186.02N

7 0

2 years ago