Same chapter4 marksDifficulty: Hard
A block and tackle system has 4 pulleys. If the efficiency is 75%, calculate the effort needed to raise a load of 900 N.
Machines
4 marksDifficulty: Hard
A machine has a velocity ratio of 6 and an efficiency of 80%. Calculate the mechanical advantage and the effort needed to raise a load of 480 N.
Original Khojo Papers practice question — not from a past board paper.
Answer
Mechanical advantage 4.8 and effort 100 N
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Efficiency = MA ÷ VR, so MA = 0.8 × 6 = 4.8. Effort = load ÷ MA = 480 ÷ 4.8 = 100 N.
Related questions
From the same topic and chapter, at a similar level.
Same chapter3 marksDifficulty: Medium
A machine raises a load of 300 N with an effort of 100 N. Calculate its mechanical advantage.
Machines
Same chapter2 marksDifficulty: Easy
Define mechanical advantage, velocity ratio and efficiency of a machine.
Machines
Same chapter3 marksDifficulty: Medium
Why is the efficiency of a practical machine always less than 100%?
Machines
Same chapter3 marksDifficulty: Medium
In a machine the effort moves 5 m while the load moves 1 m. Calculate the velocity ratio.
Machines
Same chapter3 marksDifficulty: Medium
State the velocity ratio of a single fixed pulley and of a single movable pulley, and give one use of each.
Machines