Answer:
The height of the image of the candle is 20 cm.
Explanation:
Given that,
Size of the candle, h = 12 cm
Object distance from the candle, u = -6 cm
Focal length of converging lens, f = 15 cm
To find,
The height of the image of the candle.
Solution,
Firstly, we will find the image distance of the candle. Let it is equal to v. Using lens formula to find the image distance.
v is image distance
If h' is the height of the image. Magnification is given by :
So, the height of the image of the candle is 20 cm.
Answer:
average force = 385,140 N
Explanation:
from the question we are given the following
mass (m) = 1800 kg
distance of fall (d) = 3 m
driven distance (l) = 14.4 cm = 0.144 m
acceleration due to gravity (g) = 9.8 m/s^{2}
work done = average force x driven distance.....equation 1
and
work done = change in kinetic energy + change in potential energy
work done = (0.5 x m x (v^{2} - u^{2})) + (m x g x (-d-l))
- Initial velocity (u) and final velocity (v) are zero because the pile driver is it rest before it moves to hit the pile and after hitting the pile.
- The changes in length for the potential energy are negative because the pile moves downward
we now have work done = (m x g x (-d-l))...equation 2
now equating the two equations for work done we have
average force x driven distance = (m x g x (-d-l))
average force x 0.144 = 1800 x 9.8 x (-3-0.144)
average force = (1800 x 9.8 x (-3-0.144)) ÷ 0.144
average force = 385,140 N
The biggest thing you're doing wrong is ignoring the units
when you're working with the quantities.
Now let's look at the rest of the problem:
The formula you used is correct:
Net flux through the surface = (net charge inside) / ε₀
and ε₀ = 8.85 x 10⁻¹² farad/meter.
What's the net charge inside the surface in this problem ?
It's (5.85 x 10⁷ electrons) x (the charge on each electron)
= (5.85 x 10⁷ electrons) x (-1.6 x 10⁻¹⁹ coulomb/electron)
= -9.36 x 10⁻¹² coulomb .
Finally, (net charge inside) / ε₀
= (-9.36 x 10⁻¹² coulomb) / (8.85 x 10⁻¹² farad/meter)
= -1.058 newton-m²/coulomb .
The sign and the significant figures in your answer are correct, so
we can see that you know what you're doing. The only thing left is
the order of magnitude. You most likely took one of the negative
exponents and made it positive. You got an answer that's 10²² too
small. Big deal. You could claim "that's close", and see whether you
can convince a teacher.
Answer:
surface temperature of the chip located 120 mm Ts=42.5°C
surface temperature of the chip in Mexico Ts=46.9°C
Explanation:
from the energy balance equation we have to:
q=E=30W
from Newton´s law:
Ts=Tα+(q/(h*A)), where A=l^2
N=h/k=0.04*(Vl/V)^0.85*Pr^1/3
data given:
l=0.12 m
v=10 m/s
k=0.0269 W/(m*K)
Pr=0.703
Replacing:
h=0.04*(0.0269/0.12)*(10*0.12)/((16*69x10^-6))^0.85*(0.703^1/3) = 107 W/m^2*K
The surface temperature at sea level is equal to:
Ts=25+(30x10^-3/107*0.004^2)=42.5°C
h=0.04*(0.0269/0.12)*((10*0.12)/(21*81x10^-6))^0.85*(0.705^1/3)=85.32 W/(m*K)
the surface temperature at Mexico City is equal to:
Ts=25+(30x10^-3/85.32*0.004^2)=46.9°C
