Question

The velocities of a body moving along a straight line with a constant acceleration are 10 ms -1 at t = 4s and 20 ms-1 at t = 9s. The velocity of the body at t = 1 s is


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Answer 1

Answer:

we know slope of velocity graph gives acceleration

acceleration is constant i.e slope of vt graph is constant

accceleration=Δv/Δt

                      =(20-10)/(9-4)

                       =2m/s²

now acceleration is diven by

a=dv/dt

or,  dv=adt

integrating both sides at t=4,v=10 and t=1,v=v(say)

$\int\limits^v_{10} {} \, dv =\int\limits^1_4 {a} \, dt$

or,$\int\limits^v_{10} {} \, dv =\int\limits^1_4 {2} \, dt$

or, v-10=2(1-4)

or, v=10-6

     v=4m/s

Answer 2

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