Final answer:
The explicit formula for the arithmetic sequence is An = 15 + 5(n - 1). Additional information is needed to determine the functional form of the acceleration and the instantaneous velocity and acceleration at specific times.
Step-by-step explanation:
The explicit formula for the arithmetic sequence in function form is An = 15 + 5(n - 1). To find the functional form of the acceleration, we need additional information as this sequence is related to arithmetic progression. Therefore, we cannot answer the question on the functional form of the acceleration with the given information.
To find the instantaneous velocity at t = 1, 2, 3, and 5 s, substitute the given values of n into the formula An = 15 + 5(n - 1). For example, when t = 1, substitute n = 1 and calculate A1 = 15 + 5(1 - 1) = 15.
To find the instantaneous acceleration at t = 1, 2, 3, and 5 s, as mentioned earlier, we need additional information. Therefore, we cannot answer this question without further details.
Regarding the interpretation of the results of (c) in terms of the directions of the acceleration and velocity vectors, we need the values of instantaneous acceleration at t = 1, 2, 3, and 5 s, which we currently don't have.
Thus, we cannot interpret the results without additional information.