# Question #17e5c

Mar 22, 2017

Train B

#### Explanation:

Let's focus on Train B. Train B's initial velocity is $8 \frac{m}{s}$ and acceleration is $1 \frac{m}{s} ^ 2$. We also have $t = 10$ We need Train B's final velocity:

Use the equation $a = \frac{v f - v i}{t}$

$1 = \frac{v f - 8}{10}$

$10 = v f - 8$

$v f = 18 \frac{m}{s}$

$18 \frac{m}{s}$ is greater than $16 \frac{m}{s}$ so Train B goes faster.

Mar 26, 2017

Train B

#### Explanation:

Train A's speed is constant so its speed after 10 seconds would be $16 \frac{m}{s}$, but train B which starts at $8 \frac{m}{s}$ accelerates at $1 \frac{m}{s} ^ 2$
so after 10 seconds it picks up additional $10 \frac{m}{s}$ of speed to $18 \frac{m}{s}$. Hence B will have greater speed.