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3 years ago

How long was a 60 W light bulb turned on if it used a total of 580 J of energy?

1 answer:

7 0

Here's the tool you need. You can't answer the question without this:

   "1 watt"
means
   "1 joule of energy, generated, used, or moved, every second".

So 60 watts = 60 joules per second

   Total energy generated,
      used, or moved = (power) x (time).

   580 joules = (60 watts) x (time)

Divide each side
by (60 watts): Time = (580 joules) / (60 joules/sec)

   = (9 and 2/3) seconds .

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A rope is shaken and produces 2 waves each second. Calculate the time period of the rope waves.

motikmotik

Answer:

0.5 s

Explanation:

From the question given above, the following data were obtained:

Number of circle (n) = 2

Time (t) = 1 s

Period =?

Period of a wave is simply defined as the time taken to make one complete oscillation. Mathematically, it can be expressed as:

T = t / n

Whereb

T => is the period

t => is the space time

n => is the number of circle or oscillation.

With the above formula, we can obtain the period of the wave as follow:

Number of circle (n) = 2

Time (t) = 1 s

Period =?

T = t / n

T = 1 / 2

T = 0.5 s

Thus, the period of the wave is 0.5 s

7 0

3 years ago

Most earthquakes occur in areas close to where tectonic plates meet. There are earthquakes in San Francisco. What can be conclud

earnstyle [38]

B. To have an earthquake there must be a fault line (where two or more tectonic plates meet) so if San Fran. has earthquakes they’re on a fault line.

5 0

3 years ago

Read 2 more answers

A wind turbine works by slowing the air that passes its blades and converting much of the extracted kinetic energy to electric e

ddd [48]

Answer:

2649600 Joules

Explanation:

Efficiency = 40%

m = Mass of air = 92000 kg

v = Velocity of wind = 12 m/s

Kinetic energy is given by

$K=\frac{1}{2}mv^2\\\Rightarrow K=\frac{1}{2}\times 92000\times 12^2\\\Rightarrow K=6624000\ J$

The kinetic energy of the wind is 6624000 Joules

The wind turbine extracts 40% of the kinetic energy of the wind

$E=0.4\times K\\\Rightarrow E=0.4\times 6624000\\\Rightarrow E=2649600\ J$

The energy extracted by the turbine every second is 2649600 Joules

8 0

3 years ago

Which of the following is true for the angular momentum of rotating bicycle wheel

Blababa [14]

<span>Is the following sentence true or false? Newton's first law does object's mass concentration and its axis of rotation increases, its rotational inertia The bicycle wheels at rest have no angular momentum, and the bicycle will fall over easily.</span><span>
</span>

5 0

3 years ago

Consider a uniform horizontal wooden board that acts as a pedestrian bridge. The bridge has a mass of 300 kg and a length of 10

gayaneshka [121]

Answer:

F = 2123.33N

Explanation:

In order to calculate the torque applied by the left support, you take into account that the system is at equilibrium. Then, the resultant of the implied torques are zero.

$\Sigma \tau=0$

Next, you calculate the resultant of the torques around the right support, by taking into account that the torques are generated by the center of mass of the wooden, the person and the left support. Furthermore, you take into account that torques in a clockwise direction are negative and in counterclockwise are positive.

Then, you obtain the following formula:

$-\tau_l+\tau_p+\tau_{cm}=0$ (1)

τl: torque produced by the left support

τp: torque produced by the person

τcm: torque produced by the center of mass of the wooden

The torque is given by:

$\tau=Fd$ (2)

F: force applied

d: distance to the pivot of the torque, in this case, distance to the right support.

You replace the equation (2) into the equation (1) and take into account that the force applied by the person and the center of mass of the wood are the their weight:

$-Fd_1+W_pd_2+W_{cm}d_3=0\\\\d_1=6.0m\\\\d_2=2.0m\\\\d_3=3.0m\\\\W_p=(200kg)(9.8m/s^2)=1960N\\\\W_{cm}=(300kg)(9.8m/s^2)=2940N$

Where d1, d2 and d3 are distance to the right support.

You solve the equation for F and replace the values of the other parameters:

$F=\frac{W_pd_2+W_d_3}{d_1}=\frac{(1960N)(2.0m)+(2940N)(3.0m)}{6.0m}\\\\F=2123.33N$

The force applied by the left support is 2123.33 N

8 0

3 years ago