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secondary 4 | A Maths
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secondary 4 chevron_right A Maths chevron_right Singapore

Physics Qn! Please explain to me why answer is A :) Thank you!

Date Posted: 5 years ago
Views: 242

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Dominic Chandar
Dominic Chandar's answer
17 answers (A Helpful Person)
1st
note--car 2 starts from rest, so initial velocity is 0.

car 1 is having constant speed so acceleration=0.
xy
Xy
5 years ago
what does u, t and a mean ?
Dominic Chandar
Dominic Chandar
5 years ago
u is the initial speed
a is the acceleration
t is time
xy
Xy
5 years ago
Why must times half?
Dominic Chandar
Dominic Chandar
5 years ago
good question, but that's the formula. You need to look.carefully on how it is derived. Do you want me to show it?
xy
Xy
5 years ago
Yes please :)
Dominic Chandar
Dominic Chandar
5 years ago
distance travelled = average velocity * time

average velocity=1/2(initial+final)

initial = u

final= u + a*t, ( a being acceleration)

so average velocity= u + (1/2)at

distance travelled = ut + (1/2)a*t*t

This is the most primitive way of deriving. There are other ways depending on your understanding...
xy
Xy
5 years ago
Is there another method to find distance travelled by Car2?
Arnold K H Tan
Arnold K H Tan
5 years ago
Nice attempt.. but the s = ut + 0.5at^2 formula is no longer used for both Pure and combined science Physics. But useful to learn, to solve such MCQ questions faster. Sketch out the situation and work out the answer from fundamentals.
xy
Xy
5 years ago
How to sketch?