B) it is going straight nothing is acting on it
When the car starts moving it acquires kinetic energy.
For this problem the formula of kinetic energy is:
Where m is the mass of the car = 850kg, and v is the speed of the car.
If we consider insignificant the energy lost by friction with soil and air we can propose the following equation:
Applied energy = Kinetic energy acquired by the car.
The velocity is 5.531 m/s
The car travels a distance <em>d</em> from rest with acceleration <em>a</em> after time <em>t</em> of
<em>d</em> = 1/2 <em>a</em> <em>t</em>²
It covers 69 m with 2.8 m/s² acceleration, so that
69 m = 1/2 (2.8 m/s²) <em>t</em>²
<em>t</em>² = 2 (69 m) / (2.8 m/s²)
<em>t</em> ≈ 7.02 s
where we take the positive square root because we're talking about time *after* the car begins accelerating.
As the temperature decreases, the rate of radiation goes down, but the radiation exists as long as the temperature is above the absolute zero, which is actually 0 Kelvin. 0 Kelvin equals -273°C or -460°F. All objects in the world radiate if above that temperature.
