Question

Running with an initial velocity of +11m/s, a horse has an average acceleration of -1.81m/s square. How long does it take for the horse to decrease its velocity to +6.5m/s

Answer 1

Given:

Initial velocity = 11 m/s

Average acceleration = -1.81 m/s²

Let's determine how long it takes the horse to decrease its velocity to 6.5 m/s.

Apply the equation of motion:

$v=u+at$

Where:

v is the final velocity = 6.5 m/s

u is the initial velocity = 11 m/s

a is the acceleration = -1.81 m/s²

t is the time in seconds.

Thus, we have:

$\begin{gathered} 6.5=11+(-1.81)t \\ \\ 6.5=11-1.81t \end{gathered}$

Let's solve for t.

Subtract 11 from both sides:

$\begin{gathered} 6.5-11=11-11-1.81t \\ \\ -4.5=-1.81t \\ \\ \text{Divide both sides by -1.81:} \\ \frac{-4.5}{-1.81}=\frac{-1.81t}{-1.81} \\ \\ 2.49=t \\ \\ t=2.49\text{ seconds} \end{gathered}$

Therefore, it took the horse approximately 2.49 seconds to decrease its velocity to 6.5 m/s

ANSWER:

2.49 seconds.