A body is projected up vertically with a velocity of 60 m/s. What percentage of its initial kinetic energy is converted into potential energy after 3 seconds? (Take g = 10 m/s^2)

Category: QuestionsA body is projected up vertically with a velocity of 60 m/s. What percentage of its initial kinetic energy is converted into potential energy after 3 seconds? (Take g = 10 m/s^2)
Editor">Editor Staff asked 1 year ago

A body is projected up vertically with a velocity of 60 m/s. What percentage of its initial kinetic energy is converted into potential energy after 3 seconds? (Take g = 10 m/s^2)
 
(a) 25 %
 
(b) 50%
 
(c) 75%
 
(d) 100%
 
I had been asked this question by my school teacher while I was bunking the class.
 
My query is from Kinetic Energy in section Work, Energy and Power of Physics – Class 11
Select the correct answer from above options 
Interview Questions and Answers, Database Interview Questions and Answers for Freshers and Experience

1 Answers
Editor">Editor Staff answered 1 year ago

Correct answer is (c) 75%
 
Best explanation: Initial KE = (1/2) x M x (60 x 60)
 
 = 1800 x M
 
From Newton’s laws;
 
s = ut + (1/2)gt^2
 
 = (60 x 3) – (10 x 3 x 3)/2
 
 = 180 – 45
 
 = 135 m
 
Potential energy at 135m (PE) = M x g x s
 
 = 1350 x M
 
So KE at 135m = Initial KE – PE
 
 = 1800M – 1350M
 
 = 450M J; This is 25% of the initial kinetic energy. Hence, 75% is converted into potential energy.


Notice: Trying to get property 'ID' of non-object in /home/fvckxqmi/public_html/wp-content/themes/blocksy/inc/single/single-helpers.php on line 17

Notice: Trying to get property 'ID' of non-object in /home/fvckxqmi/public_html/wp-content/themes/blocksy/inc/single/single-helpers.php on line 17

Notice: Trying to get property 'ID' of non-object in /home/fvckxqmi/public_html/wp-content/themes/blocksy/inc/single/single-helpers.php on line 17

Notice: Trying to get property 'ID' of non-object in /home/fvckxqmi/public_html/wp-content/themes/blocksy/inc/single/single-helpers.php on line 17
Articles: 40701