If a #2 kg# object is constantly accelerated from #0m/s# to #16 m/s# over # 9 s#, how much power musy be applied at #t= 1 #?

1 Answer
Jan 3, 2016

The power needed is #6 26/81W# or about 6.32W

Explanation:

When a force #F# is applied to an object moving at velocity #v #parallel to the force, the power needed is #P=Fv#.

The acceleration is #a=(Deltav)/(Deltat)=(16m/s-0m/s)/(9s-0s)=16/9m/s^2#

According to Newton's 2nd law the force is #F=ma=2kg*16/9m/s^2=32/9N#

Velocity at #t=1s# is #v=at=16/9m/s^2*1s=16/9m/s# and the power at this moment is #P=Fv=32/9N*16/9m/s=512/81W=6 26/81W~~6.32W#