Question

an object starting from rest travels 20m in first 2s and 100m in next 4s what will be the velocity after 7s from the start​

Answer 1

Answer:

Step-by-step explanation:

Given

Intial velocity =0m/s

Distance travelled =20m

time =2sec

From second equation of motion:

S=ut + 1/2 at²

20= 0×2+ 1/2a 2²

20=0+1/2a × 4

20=2a

a=10m/s²

velocity at the end of 2sec:

V=u+at

V=0+10*2

V=20m/s

After 4sec, it covers a distance of 100m

so,

100=20*4+1/2(a¹)4²

100=80+2a

2a¹=20

a¹=10m/s²

It shows acceleration is uniform.

So, velocity at end of 7 sec from start:

V=u+at

= 0 + 10*7

=70m/s

∴the velocity after 7 sec from the start is 70m/s

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