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4 years ago

6

At the starting gun, a runner accelerates at 1.9 m/s2 for 5.2 s. The runner’s acceleration is zero for the rest of the race. Wha

t is the speed of the runner at t = 2.0 s?

2 answers:

FinnZ [79.3K]4 years ago

7 0

Answer: 3.8m/s

Explanation: he accelerates 5.2s ,but we know that:

vf=vo+at , vo=0 , t=2s so : vf = 1.9*2 = 3.8m/s

guajiro [1.7K]4 years ago

3 0

Answer:

$3.8\text{m}/ \text{s}^2$

Explanation:

Given: At the starting gun, a runner accelerates at 1.9 m/s2 for 5.2 s. The runner’s acceleration is zero for the rest of the race.

To Find: the speed of the runner at t = 2.0 s.

Solution:

initial speed of runner( $\text{u}$ ) = $0$ $\text{m}/ \text{s}^2$

acceleration for first 5.2s of race= $1.9$ $\text{m}/ \text{s}^2$

to find speed of runner at , $\text{t}=2\text{s}$

Using first equation of motion,

$\text{v}=\text{u}+\text{at}$

putting values in the equation

$\text{v}=0+1.9\times2$

$\text{v}=3.8$ $\text{m}/ \text{s}^2$

So,

The speed of the runner at $\text{t}=2\text{s}$ , is $3.8\text{m}/ \text{s}^2$

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