Pumps & pump power worksheet with answers

Free printable Pumps & pump power worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
PQ = 25 L/sH = 12 m

A pump delivers 25 L/s of water (ρ = 1000 kg/m³) against a total head of 12 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 25 L/sH = 12 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 100 L/sH = 25 m

A pump delivers 100 L/s of water (ρ = 1000 kg/m³) against a total head of 25 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 100 L/sH = 25 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 15 L/sH = 62 m

A pump with an efficiency of 65% delivers 15 L/s of water (ρ = 1000 kg/m³) against a head of 62 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 15 L/sH = 62 mη = 65%g = 9.81 m/s²
Pshaft = kW
4.Medium
PQ = 20 L/sH = 58 m

A pump delivers 20 L/s of water (ρ = 1000 kg/m³) against a head of 58 m. The pump efficiency is 82% and the electric motor driving it has an efficiency of 92%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 20 L/sH = 58 mηpump = 82%ηmotor = 92%g = 9.81 m/s²
Pel = kW
5.Hard
300 kPa (gauge)PQ = 120 L/sΔz = 5 mL = 200 m, D = 250 mm, f = 0.025, ΣK = 6

A pump moves 120 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 5 m higher. The pipe is 200 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.025; the minor-loss coefficients add up to ΣK = 6 (entrance and exit included). Use g = 9.81 m/s². The upper tank is closed and the air above its water is at a gauge pressure of 300 kPa. Find the head H the pump must add.

Q = 120 L/sΔz = 5 mL = 200 mD = 250 mmf = 0.025ΣK = 6ptank = 300 kPa
H = m
6.Hard
PQ = 80 L/sΔz = 28 mL = 300 m, D = 200 mm, f = 0.02, ΣK = 8

A pump moves 80 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 28 m higher. The pipe is 300 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.02; the minor-loss coefficients add up to ΣK = 8 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 80 L/sΔz = 28 mL = 300 mD = 200 mmf = 0.02ΣK = 8
H = m

Answer key

  1. 1. Ph = 2.943 kW
  2. 2. Ph = 24.52 kW
  3. 3. Pshaft = 14.04 kW
  4. 4. Pel = 15.08 kW
  5. 5. H = 43.5 m
  6. 6. H = 40.56 m

Full step-by-step solutions: practise this topic on examproblems.com.