Question

If an athlete can accelerate at 2 m/s/s, how long will they need to go from rest to a speed of 8 m/s?

Answer 1

Explanation:

a = 2 ms^-2

v = 8 m/s

u = 0 m/s

t = ??

$a = \frac{v - u}{t}$

$t = \frac{v - u}{a}$

$= \frac{8 - 0}{2} = 4 {s}$

Therefore , the answer is 4 seconds.

I hope it helps you. If you have any doubts, then don't hesitate to ask.

Answer 2

Given :

• Initial velocity (u) = 0 m/s (as it go from rest)
• Final velocity (v) = 8 m/s
• Acceleration (a) = 2 m/s²

To find :

• Time (t)

According to the question,

In this question we will use Newton's first equation of motion,

→ v = u + at

Where,

• v stands for Final velocity
• u stands for Initial velocity
• t stands for Time
• a stands for Acceleration

→ Substituting the values,

→ 8 = 0 + 2 × t

→ 8 - 0 = 2t

→ 8 = 2t

→ 8 ÷ 2 = t

→ 4 = t

.°. The time is 4 seconds....

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More formula's :

Newton's first equation of motion :

• v = u + at

Newton's second equation of motion :

• s = ut + ½ at²

Newton's third equation of motion :

• v² = u² + 2as