JAMB CBT 2025 - Candidates, Schools, Centres, Resellers - Get Ready!
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076

A car of mass 800kg attains a speed of 25m/s in 20 secs. The power...

Physics
JAMB 1999

A car of mass 800kg attains a speed of 25m/s in 20 secs. The power developed in the engine is

  • A. 1 . 25 x 104 W
  • B. 2 . 50 x 104 W
  • C. 1 . 25 x 106W
  • D. 2 . 50 x 106 W
JAMB CBT 2025 - Candidates, Schools, Centres, Resellers - Get Ready!
JAMB CBT Mobile App 2025 - Free Download
JAMB CBT Software 2025 - Free Download
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
Correct Answer: Option A
Explanation

To calculate the power developed in the engine, we need to determine the work done and the time taken.

1. Calculate the final kinetic energy (KE) of the car:
   \[
   KE = \frac{1}{2}mv^2
   \]
   where \( m = 800 \text{ kg} \) and \( v = 25 \text{ m/s} \).

   \[
   KE = \frac{1}{2} \times 800 \, \text{kg} \times (25 \, \text{m/s})^2
   \]
   \[
   KE = 0.5 \times 800 \times 625 = 250000 \text{ J} \, (\text{joules})
   \]

2. Calculate the power (P)  developed in the engine using the formula:
   \[
   P = \frac{W}{t}
   \]
   where \( W \) is the work done (in this case, equal to the kinetic energy calculated) and \( t \) is the time taken.

   \[
   P = \frac{250000 \, \text{J}}{20 \, \text{s}} = 12500 \text{ W} \, (\text{watts})
   \]

Thus, the power developed in the engine is 12500 watts (or 12.5 kW).

 


Report an Error Ask A Question Download App
JAMB CBT Mobile App 2025 - Free Download
JAMB CBT Software 2025 - Free Download
JAMB CBT 2025 - Candidates, Schools, Centres, Resellers - Get Ready!
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076

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 }}
 
JAMB CBT Mobile App 2025 - Free Download
JAMB CBT 2025 - Candidates, Schools, Centres, Resellers - Get Ready!
JAMB CBT Software 2025 - Free Download
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
JAMB CBT Software 2025 - Free Download
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
JAMB CBT 2025 - Candidates, Schools, Centres, Resellers - Get Ready!
JAMB CBT Mobile App 2025 - Free Download