Ask question

Ask question

All categories

2 years ago

6

A 150 W driveway light produces 9.3 × 104 J of light energy over a 4.0 h period. If the light uses 2.06 × 106 J of energy in the

4.0 h, then what is its efficiency? Show all your work.

1 answer:

Andrej [43]2 years ago

3 0

Answer:

4.5%

Explanation:

efficiency = energy out / energy in

e = 9.3×10⁴ J / 2.06×10⁶ J

e = 0.045

You might be interested in

A cat falls from a table of height 1.3 m. What is the impact speed of the cat?

guapka [62]

Use this formula
Vf = sqrt(2gh)

5 0

2 years ago

A wooden disk of mass m and radius r has a string of negligible mass is wrapped around it. If the disk is allowed to fall and th

Tju [1.3M]

Answer:

$a = \frac{2}{3}g$

$T = \frac{mg}{3}$

Explanation:

As the disc is unrolling from the thread then at any moment of the time

We have force equation as

$mg - T = ma$

also by torque equation we can say

$TR = I\alpha$

$TR = \frac{1}{2}mR^2(\frac{a}{R})$

$T = \frac{1}{2}ma$

Now we have

$mg - \frac{1}{2}ma = ma$

$mg = \frac{3}{2}ma$

$a = \frac{2}{3}g$

Also from above equation the tension force in the string is

$T = \frac{1}{2}ma$

$T = \frac{mg}{3}$

7 0

2 years ago

Norma kicks a soccer ball with an initial velocity of 10.0 meters per second at an angle of 30.0°. If the ball moves through the

enyata [817]

<u>Answer</u>

27.7

<u>Explanation</u>

The ball was hit at an angle of 30°, with the horizontal at a speed of 10 m/s. We have to find the horizontal component of speed.

cosx = adjacent/hypotenuse

cos 30 = adjacent / 10

adjacent = 10 cos30

= 8.66 m/s ⇒ This is the horizontal speed.

Now find the horizontal distance.

Distance = speed × time

= 8.66 × 3.2

= 27.71

Answer to the nearest tenth = 27.7

4 0

2 years ago

Read 2 more answers

In Physics lab, Ellen has been given the task of constructing a simple motor. She must find common household items at home and b

Aleks [24]

Answer:

a) battery-->electrical current-->copper wire rotor -->magnet--> mechanical energy

Explanation:

6 0

2 years ago

Read 2 more answers

Floor lamps usually have a base with large inertia, while the long body and top have much less inertia. Part A If you want to sh

Novay_Z [31]

Answer:

When a an object is been rotated its resistance capacity to that rotational force is know as rotational inertia and this mathematically given as

$I = mr^2$

Where m is the mass

r is the rotation radius

For the spinning of the lamp as a baton to work the location of the center of mass of the floor lamp needs to be located

This is more likely to be located closer to base of the lamp as compared to the top, so success of spinning a floor lamp like a baton is highly likely if the lamp is grabbed closer to the base because that is where the position of its center of mass is likely to be.

Explanation:

5 0

2 years ago