Question

what is the ratio of speed of the car in situation A, B and C?
A) 1:2:4
B) 2:1:4
C) 4:2:1
D) 2:4:1​

Answer 1

We have to find the ratio of speed of the car in situation A, B and C.

solution : we know, speed is the rate of change of distance with respect to time.

in situation A,

speed of car = (distance between two consecutive points)/time interval

here you see, distance between two consecutive points always remains same and that is 2. [ ∵(4 - 2) = (6 - 4) = (8 - 6) = (10 - 8) ..]

so, the speed of car = 2 cm/1 sec = 2 cm/s ..(1)

situation B,

distance between two consecutive points = 2 - 1 = 3 - 2 = ... = 14 - 13 = 1 cm

so, the speed of car = 1cm/1 sec = 1 cm/s

situation C,

distance between two consecutive points = 8 - 4 = 12 - 8 = ... = 20 - 16 = 4 cm

so, the speed of car = 4cm/1sec = 4 cm/s

Therefore the ratio of the speed of car in situation A, B and C = 2cm/s : 1 cm/s : 4 cm/s = 2 : 1 : 4 .