A pump is to lift 18.0kg of water per mminute through a height of 3.60m. What output rating (watts) should the pump motor have?
2006-10-17 06:45:36 · 20 answers · asked by Anonymous in Science & Mathematics ➔ Physics
You'll want to check over this:
Power=Force * velocity
Force=mass * acceleration (in this case, gravity, 9.8 m/s^2)
So, P=mgv
m=18.0 kg
g=9.8m/s^2
v=3.60m/60 sec
I get 10.6 Watts. (Assumes no friction loss, heating or any other inefficiency)
2006-10-17 07:08:01 · answer #1 · answered by Anonymous · 5⤊ 0⤋
The pump should provide enough energy to lift the quantity of water from ground (point A) at given height (point B) i.e. to give the water sufficient potential energy U.
Using conservation of energy we have
E = K(B) + U(B) (1)
where is is the energy provided by the pump, K(B) the water's kinetic energy at point B and U(B) the respective kinetic energy.
By definition of Power P, we have
P = E/t or E = P*t (2)
where t is the interval of time during which energy E is offered.
Combining (1) and (2) we get
P*t = K(B) + U(B) ->
P = [ K(B) + U(B) ] / t
It is obvious that there are infinite values of P depending on the value of K(B).
Assuming that at given height water has zero velocity
(i.e. K(B)=0)
we get
P = U(B) / t ->
P = m*g*h/t
Using 10m/s^2 as a value for g we end up with the numeric result
P = 18.0 * 10 * 3.60 / 60 watts
or
P = 10.8 W
2006-10-17 15:27:13 · answer #2 · answered by fanis t 2 · 0⤊ 0⤋
1 kilogram = 9.806 650 029 Newton
work = force X Distance -:- time
=18.0 X 9.81 X 3.60 -:- 60 N-M -:- SECOND
=10.5948 Watts the pump should have
hope it makes sense for you
2006-10-17 14:51:02 · answer #3 · answered by sunil j 2 · 0⤊ 1⤋
assume that g is 10 m/s/s
18kg per minute through 3.6 meters is about 6*1.8 watts , pumps aren't terribly efficient , assume your 10.8 watts minimum requirement becomes 20 watts to account for viscous losses, cavitation, resistance in pump bearings.
2006-10-17 14:04:08 · answer #4 · answered by Anonymous · 1⤊ 1⤋
P = m * g * d / T / Eff
If Eff =1 then P = 18 * 10 * 3.6 / 60 /1 = 10.8 W
If Eff=0.6 the P = 10.8 / 0.6 = 18 W
2006-10-17 14:17:35 · answer #5 · answered by Dr. J. 6 · 2⤊ 0⤋
10.6 Watts.
18.0 kg x 9.81 m/s^2 = 176.6 N
176.6 N x 3.6 m = 635.8 J
635.8 J/min x ( 1 min / 60 s ) = 10.6 W
2006-10-17 14:51:42 · answer #6 · answered by entropy 3 · 0⤊ 0⤋
The real world will show you that you wont find a 10.6 watts motor, so go to The Home Depot and get one of 1500Watts.
They are on sale... open a credit card and get 15% extra discount,
I hope it helps....
2006-10-17 14:35:55 · answer #7 · answered by El Recio 6 · 0⤊ 3⤋
work done per minute
=mass*acc.dueto gravity*head
=18kg*9.81m/sec^2*3.6m Joules/min
=18*9.81*3.6/60 Joules/sec
=10.59Watt
2006-10-17 14:18:03 · answer #8 · answered by openpsychy 6 · 2⤊ 0⤋
1 watt = joule / sec = newton m / sec
18 kg * g = 18 * 9.8 = 176.4 newtons
176.4 N / m * 3.6 M = 635.04 NM/m
635.04 NM/m * 1m/60s = 10.58 NM/s = 10.58 joule / sec = 10.58 Watts
2006-10-17 14:01:49 · answer #9 · answered by Holden 5 · 3⤊ 1⤋
1 kilogram = 9.806 650 029 Newton
WORK=FORCE*DISTANCE/TIME
=18.0*9.81*3.60/60 N-M/SECOND
=10.5948 Watts rating should the pump motor have.
2006-10-17 14:28:58 · answer #10 · answered by Anonymous · 1⤊ 2⤋