Posted by admin on Saturday, September 6, 2008 · Leave a Comment
Sand from a stationary hopper falls on a moving conveyor belt at the rate of 5.10 kg/s as in Figure P9.72. The conveyor belt is supported by frictionless rollers and moves at a constant speed of v = 0.600 m/s under the action of a constant horizontal external force Fext supplied by the motor that drives the belt.
The conveyer belt moves to the right.
(a) Find the sand's rate of change of momentum in the horizontal direction.
N
(b) Find the force of friction exerted by the belt on the sand.
N
(c) Find the external force Fext.
N
(d) Find the work done by Fext in 1 second.
J
(e) Find the kinetic energy acquired by the falling sand each second due to the change in its horizontal motion.
J
(f) Why are the answers to parts (d) and (e) different?
A) The sand falls at a mass flow rate of m_dot.
Its change in horizontal momentum:
p_dot = m_dot*v
B) this is thus equal to the friction force from the belt on the sand.
F = m_dot*v
C) In order that the conveyor belt remain at constant velocity, the driving tension force must be equal and opposite to the friction force it delivers to the sand.
T = m_dot*v
E) KEi = roughly zero. KE_f = 1/2*m_dot*t*v^2
(NEW) Industrial Heavy Duty Roller Conveyor/Accumulator Roller Table 40 Inches, Hytrol 16" x 36" L Powered Case Roller Conveyor with 1/2 hp Drive, Versa Brand Lineshaft Driven Live Roller Conveyor 24" Wide - 106 Feet New Bands!, Rapistan Model 960 Tapered Live Roller Curve Conveyor, Rapistan Model #1102 Live Roller Conveyor 24" Wide-Nice, Buschman FKI Belt Driven Live Roller Conveyor 61 FT., Buschman FKI Belt Driven Live Roller Conveyor 24" Wide, Gold Tone Steel Conveyor Roller Mounting Track Bracket, ONE OVERHEAD CONVEYOR TROLLEY ROLLER WHEELS HOIST WINCH CHAIN DOLLY, 10 Pcs 27.4mm Outside Diameter Roller Conveyor Nylon Wheels Orange , 10 Pcs 27.4mm Outside Diameter Roller Conveyor Nylon Wheels Orange , Yellow Replacement 97 x 20mm Roller Conveyor Nylon Wheel, Paper Making Package Assembly Line 25mm x 220mm Conveyor Roller, 25mm x 220mm Carboon Steel Assembly Line Conveyor Roller, Paper Making Package Assembly Line 25mm x 220mm Conveyor Roller, Conveyor 12' x 8" Belt on Rollers New, NON-POWERED GRAVITY SKATE ROLLER CONVEYOR COLLAPSIBLE FROM 10' TO 40', conveyor powered roller spur 30 degree 24" wide, Used gravity conveyor 50.5" x 120" roller conveyor 1.9" on 2" centers, Lot of 4 9-1/2" L X 1-3/8" OD Conveyor Rollers, HYTROL ROLLER CONVEYOR SECTION, 2" ROLLERS (1" BALL)., HYTROL ROLLER CONVEYOR 12 X 25 SECTIONS 2" ROLLERS (1" BALLS)., 30 INCH BELT OVER ROLLER CONVEYOR, 1000S OF FEET AVAILABLE, Rapistan+Sturdi-Bilt 12" + 18" Wide Roller Skate Aluminum+Steel Gravity Conveyor, 10 Pcs 27.4mm Outside Diameter Roller Conveyor Nylon Wheels Orange , 10 Pcs Orange 27.4 x 3mm Roller Conveyor Nylon Wheels, 10 Pcs Orange 27.4 x 3mm Roller Conveyor Nylon Wheels, 97mm Outside Diameter Roller Conveyor Nylon Wheel Yellow, Paper Making Package Assembly Line 25mm x 220mm Conveyor Roller, Used Gravity Roller Conveyor 29.5" x 10', Chicago, Hytrol powered roller conveyor 90 degree curve 1 1/2 ft wide 3'3" curve 4' str, Powered Roller Hytrol Conveyor 8 x 1 1/2 feet adjustable height Reliance Electri, Stainless Steel Adjustable Roller Table Conveyor 6" Brand New, 2010 Power Roller Conveyor 10' x 41" Sharp, Greenlee 637 24" Radius Right Angle Conveyor Sheave Cable Puller Roller, Voith Paper Mill Machine Processor Wet End Area Conveyor Press Roller Sandy Hill, CUSTOM STEEL MULTI-ROLLER BEARING CONVEYORS PART FEEDER, ROLL-TOP CONVEYOR TABLES ROLLING SHELVES ROLLER SHELF LOT W/ STANDS AND HARDWARE, 200 ft. of 21" wide 10' long Roller Conveyor, Aluminum Roller Conveyor w/Stands 5pc-10' ,2-6' Long 24-1/4"W Lot of 7+++, Flexible Gravity Roller Conveyor Height 940mm Roller Dia 50mm T1732L, Conveyit Flex Roller Spiral Flexible Skate Truck Warehouse Conveyor 20'x18"GUAR!, 10 Pcs Orange 27.4 x 3mm Roller Conveyor Nylon Wheels, 25mm x 220mm Carboon Steel Assembly Line Conveyor Roller, Paper Making Package Assembly Line 25mm x 220mm Conveyor Roller, Paper Making Package Assembly Line 25mm x 220mm Conveyor Roller, *NEW* Mathews 30" x 3-1/2" Heavy Duty Gravity Conveyor Rollers 2500 lb. cap each, LEWCO Ball Transfer Conveyor 8 Feet Long 216 Roller Turn Balls, 20" Roller Conveyor 90 Dgeree Curves, Gravity Box Case Conveyor, Mfg by Roach, WEBB 26" X 120" POWERED ROLLER CONVEYOR ,
