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3 years ago

Please explain this.

Physics

1 answer:

White raven [17]3 years ago

8 0

The difference between the maximum and minimum values of voltage V across the 3 ohm resistor would be 9V.

To find the minimum and maximum values of V across the 3 ohm resistor, you will need to use Ohm’s Law, V=IR.

You already know the resistance is 3 ohms across the resistor; in order to calculate the maximum/minimum voltage across it, you will need to work out the maximum/minimum current of the series circuit.

Using Ohm’s Law to find the maximum and minimum current:

I = V/R

Where:

V = 12V (this is the emf, no volts are lost to the cell because the cell has a negligible internal resistance therefore all the 12V is transferred to the resistors in the circuit.)

The value for R however, changes due to the resistance in the variable resistor varying from 0 to 9 ohms.

The minimum value of R would be 3 ohms, where the resistance of the variable resistor is 0. Therefore total resistance = 3 + 0 = 3 ohms

Maximum value of R would be 12 ohms, where the resistance of the variable resistor is at a maximum of 9 ohms. Therefore total resistance = 3 + 9 = 12 ohms

The rest of the explanation is in the picture, hope it makes sense

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3 years ago

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mote1985 [20]

Answer:

The ball will drop 0.881 m by the time it reaches the catcher.

Explanation:

The position of the ball at time "t" is described by the position vector "r":

r = (x0 + v0x · t, y0 + v0y · t + 1/2 · g · t²)

Where:

x0 = initial horizontal position.

v0x = initial horizontal velocity.

t = time.

y0 = initial vertical position.

v0y = initial vertical velocity.

g = acceleration due to gravity (-9.8 m/s² considering the upward direction as positive).

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The x-component of the vector "r final", "rx final", will be 17.0 m. We have to find the y-component.

Using the equation of the x-component of the position vector, we can calculate the time it takes the ball to reach the catcher (notice that the frame of reference is located at the throwing point so that x0 and y0 = 0):

x = x0 + v0x · t

17.0 m = 0 m + 40.1 m/s · t

t = 17.0 m/ 40. 1 m/s = 0.424 s

With this time, we can calculate the y-component of the vector "r final", the drop of the ball:

y = y0 + v0y · t + 1/2 · g · t²

Initially, there is no vertical velocity, then, v0y = 0.

y = 1/2 · g · t²

y = -1/2 · 9.8 m/s² · (0.424 s)²

y = -0.881 m

The ball will drop 0.881 m by the time it reaches the catcher.

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