Answer:
The doorbell transforms electrical energy into sound.
Explanation:
The doorbell MAY turn electrical energy into motion of a striker which then impacts a resonator creating sound. However all door bells do not have solenoids. Some are electronic playing recordings when activated.
All doorbells do produce sound, though.
Answer:
20cm
Explanation:
A convex lens has a positive focal length and the object placed in front of it produce both virtual and real image <em>(image distance can be negative or positive depending on the nature of the image</em>).
According to the lens equation
where;
f is the focal length of the lens
u is the object distance
v is the image distance
If the magnification is - 0.6
mag = v/u = -0.5
v = -0.5u
since v = 10cm
10 = -0.5u
u = -10/0.5
u =-20 cm
Substitute u = -20cm ( due to negative magnification)and v = 10cm into the lens formula to get the focal length f
Hence the focal length of the convex lens is 20cm
Answer:
i/f = i/o + i/i f = focal, o = object, i = image
1 / i = 1 / f - 1 / o = (o - f) / o f
i = o * f / ( o - f) image distance
i = 12.5 * 22 / (12.5 - 22) = -28.9 cm
Image is real
Image is 28.9 cm to left of lens
M = - i / o = = 28.9 / 12.5 = 2.3 magnification (convex lens)
I do not agree with the statement.
The "substance" can be a compound. It's "pure"
as long as there's nothing else in it but its name.
'Pure' water is 100% H₂O with nothing else in it.
'Pure' table salt is 100% NaCl with nothing else in it.
'Pure' carbon dioxide is 100% CO₂ with nothing else in it.
These example substances are all compounds, not elements.
F = 2820.1 N
Explanation:
Let the (+)x-axis be up along the slope. The component of the weight of the crate along the slope is -mgsin15° (pointing down the slope). The force that keeps the crate from sliding is F. Therefore, we can write Newton's 2nd law along the x-axis as
Fnet = ma = 0 (a = 0 no sliding)
= F - mgsin15°
= 0
or
F = mgsin15°
= (120 kg)(9.8 m/s^2)sin15°
= 2820.1 N
