Question

a 150 - kg object takes 90 seconds to travel a 2,500 - meter straight path. it begins the trip traveling 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: Identify known values

Initial velocity $v_0 = 120\ \text{m/s}$, final velocity $v = 20\ \text{m/s}$, time $t = 90\ \text{s}$

Step2: Use acceleration formula

Acceleration $a = \frac{v - v_0}{t}$

Step3: Calculate acceleration

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

Answer:

-1.11 m/s²