Saturday, December 3, 2016

Car X is travelling at half the speed of car Y. Car X has twice the mass of car Y.






Question 1
Car X is travelling at half the speed of car Y. Car X has twice the mass of car Y.
Which statement is correct?
A Car X has half the kinetic energy of car Y.
B Car X has one quarter of the kinetic energy of car Y.
C Car X has twice the kinetic energy of car Y.
D The two cars have the same kinetic energy.



Reference: Past Exam Paper – June 2004 Paper 1 Q17




Solution 1:
Answer: A.

Let the speed of car X = v.                 Speed of car Y = 2v
Let the mass of car X = 2m.               Mass of car Y = m

Kinetic energy = ½ mv2
KE of car X = ½ (2m) v2 = mv2
KE of car Y = ½ (m) (2v)2 = 2 mv2  

No comments:

Post a Comment

If it's a past exam question, do not include links to the paper. Only the reference.
Comments will only be published after moderation

Currently Viewing: Physics Reference | Car X is travelling at half the speed of car Y. Car X has twice the mass of car Y.