R = distance
dr/dt speed or with a direction, velocity
d(dr/dt)/dt = the time derivative of the velocity is called acceleration.
Speed is a scalar. Acceleration is a vector.
Answer:
Enthalpy at outlet=284.44 KJ
Explanation:


We need to Find enthalpy of outlet.
Lets take the outlet mass m and outlet enthalpy h.
So from mass conservation

m=1+1.5+2 Kg/s
m=4.5 Kg/s
Now from energy conservation

By putting the values

So h=284.44 KJ