Question

How long would it take for a crying child to increase its roll from 6.3 m/s to 10.5 m/s if it can accelerate at 0.2 m/s²?

Answer 1

Solve it using the first equation of motion i.e.

`\tt \: v = u + at`

We have;

• v = 10.5 m/s
• u = 6.3 m/s
• a = 0.2 m/s

`\sf \: 10.5 = 6.3 + 0.2t`

`\sf \: 10.5 - 6.3= 0.2t`

`\sf \: 4.2= 0.2t`

`\sf \:t = 21 \: sec`