If a #2 kg# object is constantly accelerated from #0m/s# to #18 m/s# over # 6s#, how much power musy be applied at #t= 4 #?

1 Answer
Sep 21, 2017

The power is #=72W#

Explanation:

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

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

The final velocity is #v=18ms^-1#

The time is #t=6s#

To calculate the acceleration, apply the equation of motion

#v=u+at#

#=>#, #a=(v-u)/t=(18-0)/6=18/6=3ms^-2#

According to Newton`s Second Law of motion,

#F=ma#

The force is

#F=2*3=6N#

The speed at #t=4# is

#v=u+at=0+3*4=12ms^-1#

The power is

#P=Fv=6*12=72W#