A car traveling at 25 m/s starts to decelerate steadily. It comes to a complete stop in 6 seconds. What is its acceleration? Your Answer: Question 2 options: Answer units
Since the acceleration of the car is constant, the car is moving by uniformly accelerated motion, and the velocity of the car at time t can be written as [tex]v(t) = v_0 + at[/tex] where [tex]v_0 = 25 m/s[/tex] is the initial velocity of the car a is the acceleration t is the time At time [tex]t = 6 s[/tex], the velocity of the car is zero: [tex]v(t)=0[/tex], so we can re-arrange the previous formula to get the acceleration of the car [tex]a=- \frac{v_0}{t}=- \frac{25 m/s}{6 m/s}=-4.17 m/s^2 [/tex] and the negative sign means the direction of the acceleration is against the direction of motion of the car (in fact, the car is decelerating).
