WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Your School's Whatsapp Group - Join Us now

A simple pendulum has a period of 17.0s. When the length is shorten by 1.5m,...

Physics
JAMB 2000

A simple pendulum has a period of 17.0s. When the length is shorten by 1.5m, its period is 8.5s. Calculate the original length of the pendulum
  • A. 4.0 m
  • B. 3.0 m
  • C. 2.0 m
  • D. 1.5 m
Post UTME Past Questions Agent
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Correct Answer: Option C
Explanation
For a simple pendulum, the period T = 2π
  1/g 

Since g, 2 and π are constant, => T ∝ √l
∴ T = K√l
Let the original length = l
thus for the length l, period T = 17s
∴ 17 = K√1 .................. [1]
Again, for the new length [1 - 1.5]
the period T = 8.5s
∴ 8.5 = k
 [1-1.5] ...............[2]

thus dividing eqn [1] by eqn[2] we have
17/8.5 = √(l/l-1.5)
∴2 = √(l/l-1.5)
=>4 = (l/l-1.5)
∴l = 4[l-1.5]
= 4l - 6.0
∴4l - l = 6.0
3l = 6.0
l = 2.0m

There is an explanation video available below.


Report an Error Ask A Question Download App
Your School's Whatsapp Group - Join Us now
Post UTME Past Questions Agent
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now

Explanation Video

Your School's Whatsapp Group - Join Us now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Post UTME Past Questions Agent

Contributions ({{ comment_count }})

Please wait...

{{ settings.no_comment_msg ? settings.no_comment_msg : 'There are no comments' }}

Quick Questions

Post your Contribution

Please don't post or ask to join a "Group" or "Whatsapp Group" as a comment. It will be deleted. To join or start a group, please click here

{{ quote.posted_by.display_name }}
{{ settings.form_textarea_description }}
 
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Your School's Whatsapp Group - Join Us now
Post UTME Past Questions Agent
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Post UTME Past Questions Agent
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Your School's Whatsapp Group - Join Us now