Power can be defined as
2 answers:
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Answer:
0.39
Explanation:
Parameters given:
Mass of car, m = 940 kg
Speed of car, v = 11.8 m/s
Power supplied by engine, P = 4300 W
To get the acceleration, we must define the relationship between Power and velocity.
Power, P, is given in terms of velocity, v, as:
P = F * v
where F = force
This is because Power is given as:
(where E = energy. t = time taken, d = distance moved)
Force, F, is given as:
F = m*a
Therefore, Power will be:
P = m * a * v
Acceleration, a, will then be:
The acceleration of the car at that time is 0.39
That's true.
In fact, the resistance of a wire is given by:
where
is the resistivity of the material
L is the length of the wire
A is the cross-sectional area of the wire
We see that the resistance of the wire is inversely proportional to the cross-sectional area: A. Therefore, the narrower the wire, the smaller A, the larger the resistance. But higher resistance means that the current flowing through the wire is lower, therefore the flow of electrons in the circuit is slower, and the initial sentence is true.
In fact, the resistance of a wire is given by:
where
L is the length of the wire
A is the cross-sectional area of the wire
We see that the resistance of the wire is inversely proportional to the cross-sectional area: A. Therefore, the narrower the wire, the smaller A, the larger the resistance. But higher resistance means that the current flowing through the wire is lower, therefore the flow of electrons in the circuit is slower, and the initial sentence is true.