A particle P moves in a straight line. Velocity v ms^-1 at time t s is given by #v=5t(t-2)# for #0<t<4# #v=k# for #4<t<14# #V=68-2t# for #14<t<20# Find the set of values of t for which acceleration is positive?

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Answer 1 · 2018-05-16T06:01:01

The acceleration is positive when #t in (1,14)#

The acceleration is the derivative of the velocity

#{(v(t)=5t^2-10t),(v(t)=k),(v(t)=68-2t):}#

The acceleration is

#{(a(t)=10t-10),(a(t)=1),(a(t)=-2):}#

#a(t)>0# when # t in (1,14)#