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3 years ago

PLEASE HELP, I am desperate. This part of the presentation I am completely lost with. It is STEP 6, I got the rest finished.

Physics

1 answer:

yKpoI14uk [10]3 years ago

5 0

Answer:

Explanation:

Ok, pick some idea from here

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=10&ved=2ahUKEwjWoLaFypvnAhUowlkKHXZrCMkQFjAJegQIBBAB&url=https%3A%2F%2Fwww.wappingersschools.org%2Fcms%2Flib%2FNY01001463%2FCentricity%2FDomain%2F1552%2FGravity.ppt&usg=AOvVaw1N8kqPWy6ERpA3LNbbepit

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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

3 years ago

Read 2 more answers

A 4kg watermelon is dropped from a height of 45m. What is the velocity of the watermelon just before it hits the ground?

Makovka662 [10]

Answer:

v=30 m/s

Explanation:

h - height

g - acceleration due to gravity=10

t - time

v- velocity

$h = \frac{1}{2} \times g \times t {}^{2}$

45 = 5t²

t² = 9

t=3 seconds

v=g×t

v=10×3

v=30 m/s

3 0

3 years ago

Can anyone answer this fast pls

nekit [7.7K]

I believe the answer would be 4.5. because it wouldnt be c or d. and 2 seems too small.

3 0

3 years ago

A mercury thermometer is constructed as

Tamiku [17]

Answer:

The change in height of the mercury is approximately 2.981 cm

Explanation:

Recall that the formula for thermal expansion in volume is:

$\frac{\Delta V}{V_0} =\alpha_V\, \Delta\, T\\\Delta V = V_0\,\, \alpha_V\,\,\Delta C$

from which we solved for the change in volume $\Delta V$ due to a given change in temperature $\Delta T$

We can estimate the initial volume of the mercury in the spherical bulb of diameter 0.24 cm ( radius R = 0.12 cm) using the formula for the volume of a sphere:

$V_0=\frac{4}{3} \pi \, R^3\\V_0=\frac{4}{3} \pi \, (0.12\,cm)^3\\V_0=0.007238\,cm^3$

Therefore, the change in volume with a change in temperature of 36°C becomes:

$\Delta V = V_0\,\, \alpha_V\,\,\Delta C\\\Delta V = 0.007238229\, cm^3\,(0.000182)\,(36)\\\Delta V=0.0000474248\, cm^3$

Now, we can use this difference in volume, to estimate the height of the cylinder of mercury with diameter 0.0045 cm (radius r= 0.00225 cm):

$V_{cyl}=\pi r^2\,h\\h =\frac{V_{cyl}}{\pi r^2} \\h=\frac{0.0000474248\, cm^3}{\pi \, (0.00225\,cm)^2} \\h=2.98188 \,cm$

8 0

3 years ago

An electric heater supplies 5kw of power to atank of water assume all the energy supplied is converted into heat energy and the

kicyunya [14]

Answer:

8hours 45minutes

Explanation:

Amount of heat energy used up by the electric substance = heat gained by the water.

Amount of heat energy used up by the electric substance = Power * Time

heat gained by the water. = mcΔt

m is the mass of the water in kg

c is the specific heat capacity

Δt is the change in temperature

Given parameters

Power = 5kW = 5000W

mass of water m = 500kg

c = 4200J/kgC

Δt = 100°C - 25°C = 75°C

Required

Time taken

Substituting the given parameters into the formula

Pt = mcΔt

5000t = 500*4200*75

5000t = 157,500,000

Divide both sides by 5000

t = 157,500,000/5000

t = 31,500 secs

t = (31,500/3600)hrs

t = 8.75hours

t = 8hours 45minutes

Hence it takes 8hours 45minutes to heat 500 kg of water in the tank from 25c to 100c

6 0

4 years ago