Question 27
Two cars X and Y are
positioned as shown at time t = 0.
They are travelling in
the same direction.
X is 50 m behind Y and
has a constant velocity of 30 m s-1. Y has a constant velocity of 20
m s-1.
What is the value of t when
X is level with Y?
A 1.0 s B 1.7
s C 2.5
s D 5.0
s
Reference: Past Exam Paper – June 2016 Paper 11 Q8
Solution:
Answer:
D.
Both cars X and Y are
travelling at the constant speed. Since car X is travelling faster, it would,
at one point, be level with car Y.
Let the time at which the
cars are level be t.
Speed = Distance / time
Distance = Speed × Time
Distance travelled by car
Y in this time t = 20t
Initially, car Y was 50 m
in front of car X.
Position of car Y at this
time t = 50 + 20t
The cars would be level at
the same time (t).
Distance travelled by car
X = 30t
When the cars at level,
they would be at the same position.
Position of car X = Position
of car Y
30t = 50 + 20t
10t = 50
Time t = 50 / 10 = 5.0 s
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