An object starting from rest travels 20m in first 2s and 160m in next 4s. What will be the velocity after 7s from the start.
Answers
Answer:
Given:
Initial velocity = u =0m/s
Distance traveled =S=20m
time =t=2sec.
From second equation of motion:
S=ut + 1/2 at²
20= 0*2+ 1/2a2²
20=2a
a=10m/s²
velocity at the end of 2sec:
V=u+at
=0+10*2
V=20m/s
After 4sec, it covers a distance of 160m
so,
160=20*4+1/2(a¹)4²
160=80+2a
8a¹=80
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
Step-by-step explanation:
Answer:
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Step-by-step explanation:
From s=ut+ 21 at 2
In first 2 s,
s=20m
20= 2 a(2) =2aa=10 m/s
2
Velocity at the end of 2 s is
v=u+at=0+10×2=20m/s
In next 4s, s=ut+ 2
1
a ′ t 2
160=20×4+ 2
1
a ′ (4) 2
80=8a ′
a ′ =10 m/s 2
It shows that acceleration is uniform. From v=u+at
v=0+10×7=70 m/s