WAEC Physics 2012 Objective — Question 15
Question 15 of 50 from the West African Examinations Council (WAEC) Physics 2012 Objective paper, with the correct answer and a full explanation.
Advertisement
The radius of a wheel is 30.0 cm and that of its axle is 6 cm. Calculate the effort required to lift a load of 120.0 N using this machine, assuming 100% efficiency.
- A. A. 600.0N
- B. B. 40.0N
- C. C. 24.0NCorrect
- D. D. 20.0N
Explanation
Efficiency (100%) means workdone on load = workdone by effort: E x R = F x r? Using velocity ratio = R/r = 30/6 = 5, and MA=VR at 100% efficiency, Effort = Load/MA = 120/5 = 24.0 N.
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.