Question

an object starting from rest travels 20m in 1st 2 seconds and 160m in next 4 seconds .
what will be velocity after 7 seconds from start?​

Answer 1

Explanation:

$\huge\bf{\mid{\overline{\underline{ANSWER:-}\mid}}}$

Object starts from rest therefore u = 0

It travels 20 m in first 2 secs

We can get our answer.Just by using this condition.

S = ut + 1/2 at^2

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S = displacement

t = time

a = acceleration

u = initial velocity

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S = 1/2 at^2

20 = 1/2 a (4)

a = 10 m/s^2

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For velocity at 7th second..

v = u + at

v = at

v = 10 (7)

v = 70 m/s

$\boxed{ \begin {minipage} {7 cm} </p><p>Some \: \: formulas \\ \\ \huge{ \star v = u + at} \\ \\ \huge{ \star S = ut + \frac{1}{2} a {t}^{2}} \\ \\ \huge{\star {v}^{2} = {u}^{2} + 2 a S} \end {minipage} }$