Civil Engineering - UPSC Civil Service Exam Questions - Discussion
Discussion Forum : UPSC Civil Service Exam Questions - Section 4 (Q.No. 29)
29.
A car accelerates from rest to a speed of 10 m/s and the energy spent in doing this is E. If the car is further accelerated from 10 m/s to 20m/s, what is the amount of energy to be spent further ?
Discussion:
3 comments Page 1 of 1.
Sadashiva said:
7 years ago
According to the Equation, KE=(1/2)mv^2.
The energy required to accelerate the car to 10m/s (given 'E').
Therefore mass=2E/100.
Energy required to accelerate to 20m/s=(1/2)*(2E/100)*20*20=4E.
Energy required to accelerate from 10m/s to 20m/s = 4E-1E=3E.
Therefore it is equal to 3 times the initial energy required.
The energy required to accelerate the car to 10m/s (given 'E').
Therefore mass=2E/100.
Energy required to accelerate to 20m/s=(1/2)*(2E/100)*20*20=4E.
Energy required to accelerate from 10m/s to 20m/s = 4E-1E=3E.
Therefore it is equal to 3 times the initial energy required.
Harish said:
7 years ago
E' = 1/2 m [ 20^2 - 10^2 ] = 1/2 m * 30 * 10.
E = 1/2 m * 10 * 10.
E'/ E= 3.
E' = 3E.
E = 1/2 m * 10 * 10.
E'/ E= 3.
E' = 3E.
Rocky bhai said:
4 years ago
C should be the right answer.
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