If a lathe is run at a speed of 500 rpm (revolutions per minute), how many revol

Question

If a lathe is run at a speed of 500 rpm (revolutions per minute), how many revolutions will it make in 18 minutes? One horsepower is the ability to lift 550 pounds a height of one foot in one second or one horse power is equal to 550 ft-lb/s. How many ft-lb/s are there in 32 horsepower? If an elevator is to raise a total weight of 5000 lb a height of 30 ft in 20 sec, what horsepower motor would be required? If 160 tons of coal are to be lifted 20 feet on a conveyor belt per hour, what horsepower motor is required to lift the coal? (Neglect the belt.) How many kilowatts would be required? (1 kilowatt = 1000 watts) If the cost of electricity is 9 cents per kilowatt hour, how much would it cost to un a 0.5-hp pump motor per month if the motor is run 24 hours per day?

Explanation / Answer

4) No of revolutions in 18 mins = 18 * 500 = 9000 revolutions

11) 1 hp = 550 ft-lb/sec

32 hp = 32 * 550 = 17600 ft-lb/sec

12)

Load p = 5000 lb

Height h = 30ft

time t = 20 sec

Total Work to be done

W = p*h/t

W = 5000*30/20

W = 7500 ft-lb/sec

W = 7500/550 hp

or W = 13.64 hp

14)

Load p = 160 tons = 160*2000 lbs ( 1 US ton = 2000lbs)

p = 320000 lbs

Height h = 20 ft

Time t = 1 hour

t = 3600 sec

Work Done W= ph/t

W= 320000*20/3600

W = 1777.78 hp

W = 1777.78 * 746 Watts ( 1 hp = 746 Watts)

W = 1326.22 kW is the Power required to run the conveyor

15)

Total energy consumed by pump E= 0.5 * 746 *30* 24 * 3600 Watts

E= 966816000 Joules

Cost to run the pump

C = E *0.09 / 3600000 Dollars ( 1 kW-hr = 3600000 Joules)

C = 966816000*0.09/3600000

C = 241.704 Dollars

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.