Question

question 5 (1 point)
a car travels at 15 m/s for 10 s. it then speeds up with a constant acceleration of 2.0 m/s2 for 15 s. at the end of this time, what is its velocity?
15 m/s
30 m/s
45 m/s
375 m/s

Explanation:

Step1: Identify the initial velocity

The car travels at a constant speed of \(15\ m/s\) for \(10\ s\). Then it accelerates. The initial velocity \(u\) for the acceleration phase is \(15\ m/s\) (because the speed before acceleration is \(15\ m/s\)).

Step2: Use the formula \(v = u+at\)

The formula for final velocity \(v\) in uniformly - accelerated motion is \(v = u + at\), where \(u\) is the initial velocity, \(a\) is the acceleration, and \(t\) is the time of acceleration.
Given \(u = 15\ m/s\), \(a=2.0\ m/s^{2}\), and \(t = 15\ s\).
Substitute the values into the formula: \(v=15+2\times15\).
First, calculate \(2\times15 = 30\). Then \(v=15 + 30\).

Answer:

\(45\ m/s\) (the third option)