Two balls, ball A and ball B, are dropped from the same height onto the same surface. If ball A rebounds to a higher height than
1 answer:
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Answer:
Approximately .
Approximately . (assumption: the LED here is an Ohmic resistor.)
Explanation:
The two resistors here and
are connected in parallel. Their effective resistance would be equal to
.
The current in a serial circuit is supposed to be the same everywhere. In this case, the current through the LED should be . That should also be the current through the effective
resistor. Make sure all values are in standard units. The voltage drop across that resistor would be
.
The voltage drop across the entire circuit would equal to
- the voltage drop across the resistors, plus
- the voltage drop across the LED.
In this case, that value would be equal to . That's the voltage that needs to be supplied to the circuit to achieve a current of
through the LED.
Assuming that the LED is an Ohmic resistor. In other words, assume that its resistance is the same for all currents. Calculate its resistance:
.
The resistance of a serial circuit is equal to the resistance of its parts. In this case,
.
Again, the current in a serial circuit is the same in all appliances.
.
Answer:
y = 20.38 [m]
Explanation:
In order to solve these problems, we must use the following kinematics equation.
where:
Vf = final velocity = 0
Vi = initial velocity = 72 [km/h]
g = gravity acceleration = 9.81 [m/s^2]
y = vertical elevation [m]
We need to convert [km/h] to [m/s]
Note: the negative sign of the equation means that the acceleration acts in the opposite direction to the movement of the body. And the final speed is zero, because when the body reaches the maximum height, the Stone does not move its speed has been reduced to its entirety.
0 = (20)^2 - (2*9.81*y)
20^2 = 2*9.81*y
y = 20.38 [m]