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= 9 #?

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Answer 1 · 2018-03-28T06:07:53

The power is #=28.125W#

The mass of the object is #m=2kg#

The initial velocity is #u=0ms^-1#

The final velocity is #v=15ms^-1#

The time is #t=12s#

Apply the equation of motion

#v=u+at#

#a=(v-u)/t=(15-0)/12=1.25ms^-2#

Acording to Newton's Second Law of Motion

#F=ma#

The force is

#F=2*1.25=2.5N#

When #t=9#, the velocity is

#v_9=0+1.25*9=11.25ms^-1#

The power is

#P=Fv=2.5*11.25=28.125W#