Question

in an automobile race the cars are started with a starter car traveling at 31.5 m/sec. if the lead car has an average acceleration of 4.3m/sec2 during the first 3 seconds, how fast was it traveling at the end of 3 seconds and how far did it go?

Answer 1

In an automobile race the cars are started with a starter car traveling at $31.5\mathrm{m / sec}$. If the lead car has an average acceleration of $4.3\mathrm{m / sec2}$ during the first 3 seconds, how fast was it traveling at the end of 3 seconds and how far did it go?

Solution:

Let:

$$a = 4.3 \, \mathrm{m/s^2}$$ $$t = 3 \, \mathrm{sec}$$ $$v - ?, S - ?$$ $$v = a t$$ $$S = \frac{1}{2} a t^2$$ $$v = 4.3 * 3 = 12.9 \, \mathrm{m/s}$$ $$S = \frac{1}{2} * 4.3 * 3^2 = 19.35 \, \mathrm{m}$$

Answer: velocity is $12.9 \, \mathrm{m/s}$, traveled $19.35 \, \mathrm{m}$.