An electric toy car with a mass of #2 kg# is powered by a motor with a voltage of #4 V# and a current supply of #8 A#. How fast can the toy car accelerate from rest to #3 m/s#?
1 Answer
Jun 28, 2016
The car will take
Explanation:
Voltage and current relate to power by the equation
Power in turn, relates to work by the equation
Kinetic energy is simply a measure of work and has the form
So in order to solve this, we first determine the power output of the motor. This is
Using this result and the second equation, we can rearrange terms to show that
Using the third equation and plugging in the given values, we can see that
The rest is trivial algebra. Using