Question

an object with an initial velocity of +100 m/s undergoes an acceleration of -10m/s² for ten seconds. its velocity at each second is shown. fill in the missing velocities. **make sure to include + or - signs (unless zero) in your answer, there should be no spaces in between anything. time (s) 0s 1s 2s 3s 4s velocity (m/s) +100m/s +90m/s +70m/s m/s m/s

Explanation:

Step1: Recall velocity - time formula

The formula for velocity $v = v_0+at$, where $v_0$ is the initial velocity, $a$ is the acceleration and $t$ is the time. Here, $v_0 = + 100$ m/s and $a=-10$ m/s².

Step2: Calculate velocity at $t = 2$s

Substitute $t = 2$s into the formula $v=v_0 + at$. So $v=100+( - 10)\times2=100 - 20=+80$ m/s.

Step3: Calculate velocity at $t = 4$s

Substitute $t = 4$s into the formula $v=v_0+at$. So $v=100+( - 10)\times4=100 - 40=+60$ m/s.

Answer:

2s: +80m/s
4s: +60m/s