Question

An object accelerates from 20 m/s down to 10 m/s in 5 seconds.
What is the acceleration of the object?

Answer 1

Answer:

The acceleration of the object is $-2\ \frac{m}{sec^2}$

Explanation:

we know that

The acceleration is the change in the velocity, divided by the time

Let

v -----> the change in the velocity in m/sec

t ----> the time in sec

$a=\frac{V}{t}$

we have that

$V_2=10\ m/sec\\V_1=20\ m/sec$

$V=V_2-V_1$

substitute

$V=10-20=-10\ m/sec$

$t=5\ sec$

substitute in the formula

$a=\frac{-10}{5}=-2\ \frac{m}{sec^2}$

therefore

The acceleration of the object is $-2\ \frac{m}{sec^2}$

Is negative because is a deceleration