Question

A runner has an initial velocity of 4 meters per second. After 20 seconds, the runner's velocity is 6 meters per second. Which is the runner's acceleration?
A.
1 meter/second/second in the same direction of travel
B.
0.1 meters/second/second in the same direction of travel
C.
–1 meter/second/second in the same direction of travel

Answer 1

Answer:

The acceleration of runner is $\bold{0.1 \ m / s^{2}}$ if his initial velocity is 4 m⁄s and after 20 seconds the runner's velocity is 6 m⁄s.

Option: B

Explanation:

From given we came to know that the runner starts his initial velocity is 4  , and in 20 s speeds up to 6 m⁄s, to find acceleration of runner, we know that acceleration is ratio of change in velocity to change in time.

The acceleration is given by the formula:

$\text { Acceleration }=\frac{\text { Change in velocity }}{\text { Change in time }}$

We know that change in velocity as 4 m/s to 6 m/s and change time as 20 s.

$\Rightarrow \text { Acceleration }=\frac{6-4}{20}$

$\therefore \text { Acceleration }=0.1 \ \mathrm{m} / \mathrm{s}^{2}$

Therefore, acceleration of runner will be $0.1 \ m / s^{2}$

Answer 2

Answer:

B. 0.1 meters/second/second in the same direction of travel.

Explanation:

Acceleration is the rate of change of velocity. Acceleration is a vector quantity.

a=Δv/Δt

=(v₂-v₁)/(t₂-t₁)

v₁=4 m/s

v₂=6 m/s

t₁=0 s

t₂=20 s

a=(6m/s-4m/s)/(20s-0)

= 0.1 m/s² in the same direction of travel.

Therefore acceleration =0.1 meters/second/second in the same direction of travel.