Q23 of 35 Page 55

A body travels a distance of 2 m in 2 s and 2.2 m in next 4 s. What will be the velocity of the body at the end of 7th second from the start?

Given: Distance travelled in 2 s = 2 m

Distance travelled in next 4 s = 2.2 m


To Find: Velocity at the end of 7th second


Equations Used:


..1


..2


..3


Where v = Final Velocity t = Time


u = Initial Velocity s = Distance


a = Acceleration


Case – 1: First two seconds


t = 2 s; s = 2m;


So, using 2;




..4


Case – 2: Motion in next 4 s


Now, Distance travelled = 2.2 m


Total distance in 6 s is given by = 2 + 2.2 = 4.2 m


So, s = 4.2 m and t = 6 s


Now, using 2:





..5


Solving 4 and 5, we get:


And


So, velocity after 7 seconds:


;


Using equation 1:





Hence velocity at the end of the 7th second is.


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