If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 12s#, how much power musy be applied at #t= 5 #?

1 Answer
Feb 2, 2018

For constant acceleration happened,we can apply #v=u+at#(all the symbols are bearing their conventional meaning)

Given, #u=0,v=15,t=12#

so, #a= 15/12 m/s^2#

So,force acting(#F#) on the object is #(2*15/12) N# or, #15/6 N# (using #F=ma#)

Now, power = Work done per unit time = #(F*s)/t# (#s# is the displacement in time #t#)

So,displacement at #t=5# was
#(1/2)(15/12) (5^2 ) m# (using #s=1/2at^2#)

So,power at #t=5# was #(15/6 *(1/2)(15/12) (5^2 )) /5 W# i.e #7.81 W#