The instantaneous rate of energy input to a device is watts ( )

PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

The instantaneous rate of energy input to a device is

P(t)

watts (

\text{J/s}

). A technician computes

E_1=\int_{0}^{3} P(t)\,dt,\qquad E_2=\int_{3}^{5} [P(t)+100]\,dt

and then forms

E_1+E_2

to estimate the total energy supplied from

t=0

t=5

seconds. Without evaluating either integral, determine whether

E_1+E_2

has physically meaningful units and explain, in one sentence, why or why not.