Question

A body travels 200cm in first 2s and 220cm in the next 5s. Calculate the velocity at the end of seventh second from start.(ans. 2.22ms‐¹)​

Answer 1

Answer:

Explanation:

Using Second Equation of motion;

$s=ut+\frac{1}{2} at^{2}$

⇒$200=u*2+\frac{1}{2} *a*4$    →1

Distance travelled by the body in next 5 seconds is 220cm

So the total distance travelled by the body in 7 seconds = 200+220=420cm

$420=u*7+\frac{1}{2} *a*49$

⇒$840=14u+49a$   →2

On solving equation (1) and (2)

we get u=115cm/s

$a=16 m/s^{2}$

Velocity at the end of 7th  second is given by

v = 115 + (-16)7

v = 3 cm/s

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