Question

an object starts off with a velocity of 10 m/s. it experiences a constant acceleration equal to -5 m/s². list its velocities at t = 1 second, t = 2 seconds, t = 3 seconds, and t = 4 seconds in that order.
0 m/s, -10 m/s, -20 m/s, -30 m/s
5 m/s, 0 m/s, -5 m/s, and -10 m/s
10 m/s, 7.5 m/s, 5 m/s, and 2.5 m/s
15 m/s, 20 m/s, 25 m/s, 30 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. Given $v_0 = 10\ m/s$ and $a=- 5\ m/s^{2}$.

Step2: Calculate velocity at $t = 1\ s$

Substitute $t = 1\ s$ into the formula: $v_1=v_0+at=10+( - 5)\times1=10 - 5=5\ m/s$.

Step3: Calculate velocity at $t = 2\ s$

Substitute $t = 2\ s$ into the formula: $v_2=v_0+at=10+( - 5)\times2=10-10 = 0\ m/s$.

Step4: Calculate velocity at $t = 3\ s$

Substitute $t = 3\ s$ into the formula: $v_3=v_0+at=10+( - 5)\times3=10 - 15=-5\ m/s$.

Step5: Calculate velocity at $t = 4\ s$

Substitute $t = 4\ s$ into the formula: $v_4=v_0+at=10+( - 5)\times4=10 - 20=-10\ m/s$.

Answer:

5 m/s, 0 m/s, -5 m/s, and -10 m/s