The average distance between the Sun and a certain planet is approximately 2.3 x 1014 inches. Which of the following is closest
to the average distance between the Sun and the planet, in kilometers? (1 kilometer is approximately 3.9 x 104inches.) (A) 7.1 x 10^8(B) 5.9 x 10^9(C) 1.6 x 10^10(D) 1.6 x 10^11(E) 5.9 x 10^11
Since the car speeds up at a constant rate, we can use the kinematic equation for distance (assuming that the initial position is x=0, and choosing t₀ =0), as follows:
Since the car starts from rest, v₀ =0.
We know the value of t = 5 sec., but we need to find the value of a.
Applying the definition of acceleration, as the rate of change of velocity with respect to time, and remembering that v₀ = 0 and t₀ =0, we can solve for a, as follows:
Replacing a and t in (1):
Now, if the truck slows down at a constant rate also, we can use (1) again, noting that v₀ is not equal to zero anymore.
Since we have the values of vf (it's zero because the truck stops), v₀, and t, we can find the new value of a, as follows:
Replacing v₀, at and t in (1), we have:
Therefore, as the truck travels twice as far as the car, the right answer is a).
You did not list the options. However, knowing the possible options from having seen the material myself - I can infer that the answer option is A. I apologize sincerely if this is wrong.
