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The electric appliance with a resistance of 40 ohms is connected to a power supply. Through the power of 2C, the work done by the current is 24J. What is the voltage at both ends of the power supply? What is the current through the conductor?
C means Coulomb in physics. It is the unit of electricity
First of all, several formulas must know that I = q / T, q is the electric quantity, and t is the time
Electric work w = uit = I square RT = u square ÷ R × T u is the voltage and I is the current
24J = uit = UQ u = 12V
24J = u m3 / R × T can be calculated t = 20 / 3 seconds
I = 3 / 10A
As shown in the figure, near the horizontal ground, small ball B aims at another small ball a obliquely upward at the initial speed. Just as ball B shoots out, ball a starts to fall from rest, regardless of air resistance. Then the two balls are moving in the air () A. A moves in a straight line with uniform speed change, and B moves in a variable acceleration curve B. The speed change of a must be greater than that of B at the same time C. The kinetic energy of balls a and B varies uniformly with the vertical height above the ground D. A and B are bound to collide
A. Ball a does free falling motion and uniform speed change linear motion. Ball B does oblique throwing motion and uniform speed change curve motion, so a is wrong. B. according to the formula △ v = a △ T, since the accelerations of a and B are gravity accelerations, the velocity change of a in the same time is equal to the velocity change of B, so B is wrong. C, root
I hope someone will answer the physics question. Thank you Title: if a plate of a parallel capacitor (the amount of charge on the plate remains unchanged) is connected to an electrometer, the pointer has a deflection angle θ, Now, if the distance d between the plates is changed, the voltage U between the plates increases and the angle increases θ Question: why does the constant amount of charge and the increase of voltage make the angle θ Does the charge on the plate run to the electrometer or? I hope to be more detailed. Thank you Why does the U increase the General Assembly θ enlarge
C= ε S/4πkd,
Q=U X C,
D increases, C decreases
And because Q doesn't change
Then u was big
-Please help me with this physics problem An aluminum pot has a mass of 500g and contains 2000g of 20 ℃ water. How much heat does it need to absorb to raise the water temperature to 100 ℃?
First of all, we should understand that water not only absorbs heat, but also aluminum pots absorb heat. We can add up the total heat they absorb
Get: Q absorption = q aluminum + Q water = C aluminum m aluminum. 80 ℃ + C water m water 80 ℃, calculate the result. It should be noted that the unit of mass should be converted into kg
The railway line between a and B is 2430 kilometers long. The train passes through a 1050 meter tunnel from a to B in 1 minute and 10 seconds (1) What is the average speed of the train through the tunnel? How many kilometers per hour? (2) How many hours does the train travel from place a to place B at this average speed?
(1) Known: s Tunnel = 1050m, t = 1min10s = 70s,
Then the average speed of the train passing through the tunnel is v = s
t=1050m
70s = 15m / s, and since 1m / S = 3.6km/s,
Then 15m / S = 15 × 3.6km/h=54km/h，
A: the average speed of the train passing through the tunnel is 15m / s, equivalent to 54km / h
(2) Known: s ′ = 2430km, v = 54km / h,
Then the time required for the train to drive from place a to place B at this average speed is t = s
v=2430km
54km/h=45h，
A: it takes 45 hours for the train to travel from place a to place B at this average speed
Automobile is the main means of transportation for human beings today. If the engine power P of automobile is constant at 150KW, when driving at a constant speed, the passing distance in 1min is 1.2km
w=pt =150000*60=9000000
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