If a #12 kg# object is constantly accelerated from #0m/s# to #60 m/s# over 8 s, how much power musy be applied at #t=3#?

1 Answer
Feb 5, 2018

The power is #=2025W#

Explanation:

The mass of the object is #m=12kg#

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

The final velocity is #v=60ms^-1#

The time is #t=8s#

Apply the equation of motion

#v=u+at#

To calculate the acceleration

#a=(v-u)/t=(60-0)/8=7.5ms^-1#

According to Newton's Second Law

#F=ma#

The force is

#F=12*7.5=90N#

The velocity when #t=3# is given by the equation

#v=u+at=0+3*7.5=22.5ms^-1#

The power is

#P=Fv=90*22.5=2025W#