Answer:6v
Explanation:
Current=0.30A
Resistance=20ohms
voltage=current x resistance
Voltage=0.30 x 20
Voltage=6v
Solution: (i) Density (ii) thermal
Liquids at lower temperatures have greater density when compared to liquids at higher temperatures.This is because, at higher temperatures, molecules have greater kinetic energy and hence they are spaced farther apart, when compared to molecules at lower temperatures. Thus, the colder layers of liquids are heavier than the warmer layers, which causes then to move down due to gravity. For the same reason, the hotter layers move upwards through the liquid.
When a liquid is heated, the molecules closest to the heat source have greater energy, their density becomes less and they move upwards. The colder layers sink downwards. The layers of the liquid which were cold initially, get heated and they travel upwards. As the process repeats, convection currents are set up in the liquid.
These currents transfer the thermal energy derived from the source throughout the liquid. The process stops when the entire liquid is at the same temperature.
Thus, convection currents occur in liquids due to temperature and <u>density</u> differences. Convection currents transfer <u>thermal</u> energy throughout a fluid.
Answer:
(D) 42.4N
Explanation:
Since the frame is at rest, the net force acting on it must be 0. There are three forces acting on it: the gravity and the opposing forces of the two cables.
Since the gravity is a vertical force, we are only interested in the vertical components of the remaining forces. The net force equation is
F_net = 0 = F_g -2 * F_y
The vertical force of one cable (using the information in the drawing) is:
F_y = 30N * sin 45 deg = 21.21N
Now the weight can be determined:
0 = F_g - 2 * F_y
F_g= 2 * F_y = 2 * 21.21N = 42.4N
The weight of the frame is about 42.4N.
By applying the correspondent change of scale, we will see that Earth should be placed 214.8m away from the scale sun.
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How far the Earth should be placed?</h3>
The real radius of the Sun is:
R = 696,340 km
And the radius of the scale Sun is 1m, then we have the relation:
1m = 696,340 km
1 = (1m/696,340 km)
Now, the real distance between the Sun and Earth is:
d = 149,600,000 km
If we apply the change of scale we have above, we will get:
d = 149,600,000 km*(1m/696,340 km) = 214.8m
So the Earth should be placed at 214.8m of the ball that represents the sun.
If you want to learn more about changes of scale, you can read:
brainly.com/question/15891755