If a #2# #kg# object accelerates constantly from #0# #ms^-1# to #15# #ms^-1# over #6# #s#, how much power must be applied at #t=4#?

1 Answer
Jun 18, 2017

The power is #=50W#

Explanation:

The acceleration is

#a=(v-u)/t=(15-0)/6=2.5ms^-2#

The mass is #m=2kg#

According to Newton's Second Law,

the force is #F=ma#,

#F=2*2.5=5N#

The velocity at #t=4s# is

#v=u+at=0+2.5*4=10ms^-1#

The power is

#P=Fv=5*10=50W#