How to Calculate the Kinetic Energy of a Ton of Water Moving at 60 min/hr?

[serven7]

This question is directly from David M. Himmelblau and James B. Riggs Basic Principles and Calculations in Chemical Engineering, 7th Edition cd rom workbook part1 unsolved problem q1.3. I am reworking through the basics, However when i went through this question I couldn't figure out the velocity.

Find the kinetic energy of a ton of water moving at 60 min/hr expressed as (ft)(lbf).?

Answer from booklet= 2.40*10^5 (ft) (lbf). However i can't find the velocity of the moving water i tried using gc and converting mass to slug*ft/s^2 or lbm x ft/s^2. please help!

 

[tiny-tim]

welcome to pf!

hi serven7! welcome to pf!

(try using the X² tag just above the Reply box )

Find the kinetic energy of a ton of water moving at 60 min/hr expressed as (ft)(lbf).?

erm … everything moves at 60 min/hr !

show us your full calculations, and then we'll see what went wrong, and we'll know how to help!

 

[serven7]

Find the kinetic energy of a ton of water moving at 60 min/hr expressed as (ft)(lbf).?
no velocity is listed

a ton=2000 pound mass
1hr =3600seconds(1.) 2000/32.174 = 62.2 slug mass

(2) 1 lbf = 1 slug*ft/s² so... slug mass* gc(32.2ft/s²)

(3) so KE = 0.5* slug* (ft/s²)² ,hence 0.5*62.2slug*(32.2ft/s²)² = 32246 (ft) (lbf)

Answer from booklet= 2.40*10⁵ (ft) (lbf).. answer is wrong.
Don't know what am doing wrong, question does not provide velocity.

 

[AlephZero]

I think 60 min/hr is a typo for 60 miles/hr.

At least, that velocity gives me the "right answer".

 

[serven7]

Thx, the question was doing my head in cux such a simple question and am spending so much time on it.

KE= 0.5*62.2slug*(88ft/s²)2 =240838(ft) (lbf)