Question

a 150 - kg object takes 1.5 minutes to travel a 2,500 - meter straight path. it begins the trip travelling 120 meters per second and decelerates to a velocity of 20 meters per second.
what was its acceleration?

• 1.11 m/s²
• 0.3 m/s²

+ 1.11 m/s²
+ 80 m/s²

Explanation:

Step1: Convert time to seconds

$t = 1.5\ \text{minutes}=1.5\times60\ \text{s} = 90\ \text{s}$

Step2: Use acceleration formula $a=\frac{v - u}{t}$

Here, $u = 120\ \text{m/s}$, $v = 20\ \text{m/s}$, $t = 90\ \text{s}$
$a=\frac{20 - 120}{90}=\frac{- 100}{90}\approx - 1.11\ \text{m/s}^2$

Answer:

$-1.11\ \text{m/s}^2$