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3 years ago

Approximately how much electrical energy does a 5-W light bulb convert to radiant or thermal energy in one hour

Physics

1 answer:

ch4aika [34]3 years ago

8 0

answer

18000 J

explanation

the lightbulb dissipates 5W of power

P = ΔE / Δt

rearrange to solve for energy

ΔE = PΔt

P = 5W

t = 1 hour = 60 minutes = 3600 seconds

ΔE = 5 * 3600

ΔE = 18000 J

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A hula hoop is rolling along the ground with a translational speed of 26 ft/s. It rolls up a hill that is 16 ft high. Determine

nikklg [1K]

Answer:12.8 ft/s

Explanation:

Given

Speed of hoop $v=26\ ft/s$

height of top $h=16\ ft$

Initial energy at bottom is

$E_b=\frac{1}{2}mv^2+\frac{1}{2}I\omega ^2$

Where m=mass of hoop

I=moment of inertia of hoop

$\omega$ =angular velocity

for pure rolling $v=\omega R$

$I=mR^2$

$E_b=\frac{1}{2}mv^2+\frac{1}{2}mR^2\times (\frac{v}{R})^2$

$E_b=mv^2=m(26)^2=676m$

Energy required to reach at top

$E_T=mgh=m\times 32.2\times 16$

$E_T=512.2m$

Thus 512.2 m is converted energy is spent to raise the potential energy of hoop and remaining is in the form of kinetic and rotational energy

$\Delta E=676m-512.2m=163.8m$

Therefore

$163.8 m=mv^2$

$v=\sqrt{163.8}$

$v=12.798\approx 12.8\ ft/s$

7 0

2 years ago

How do i do this is hard

Zolol [24]

Answer:

I believe it would be E)none of the above.

Explanation:

7 0

2 years ago

I need help on 7 and 8 thanks

Sauron [17]

8. 107.1 MHz

7. 90.5 MHz

5 0

3 years ago

Assume that the surface temperature of the lightbulb filament when it is plugged into an outlet of 120 V is about 3000 K and the

myrzilka [38]

Answer:

A= $8.7\times 10^{-7}m^{2}$

Explanation:

We have given power =40 W but only 10% of this power is used so actual power $P=\frac{40\times 10}{100}=4 W$

We know that from Stefan's law $p=\sigma AT^4$ where $\sigma$ is Boltzmann constant which value is $5.6\times 10^{-8}Wm^{-2}K^{-4}$

So $4=5.67\times 10^{-8}\times A\times 3000^4$

A= $8.7\times 10^{-7}m^{2}$

4 0

2 years ago

Read 2 more answers

A hot-air balloon and its basket are accelerating upward at 0.265 m/s2, propelled by a net upward force of 688 N. A rope of negl

Sergeu [11.5K]

Question:<em> </em><em>Find, separately, them mass of the balloon and the basket (incidentally, most of the balloon's mass is air)</em>

Answer:

The mass of the balloon is 2295 kg, and the mass of the basket is 301 kg.

Explanation:

Let us call the mass of the balloon $m_1$ and the mass of the basket $m_2$ , then according to newton's second law:

$(1). \:F = (m_1+m_2)a$ ,

where $a =0.265m/s^2$ is the upward acceleration, and $F = 688N$ is the net propelling force (counts the gravitational force).

Also, the tension $T$ in the rope is 79.8 N more than the basket's weight; therefore,

$(2). \:T = m_2g+79.8$

and this tension must equal

$T -m_2g =m_2a$

$(3). \:T = m_2g +m_2a$

Combining equations (2) and (3) we get:

$m_2a = 79.8$

since $a =0.265m/s^2$ , we have

$\boxed{m_2 = 301.13kg}$

Putting this into equation (1) and substituting the numerical values of $F$ and $a$ , we get:

$688N = (m_1+301.13kg)(0.265m/s^2)$

$\boxed{m_1 = 2295 kg}$

Thus, the mass of the balloon and the basket is 2295 kg and 301 kg respectively.

8 0

2 years ago