When the question says speed is increasing at a
constant rate with respect to time, it means the
amount of speed added per second is the same.
Think of it this way:
- Second 1: speed increases by
1.5 m/s
- Second 2: speed increases by
1.5 m/s
- Second 3: speed increases by
1.5 m/s
- ... and so on
This is
linear growth (arithmetic): v = v0 + (constant × time)
What you're thinking of:If V1/V0 = V2/V1 (constant ratio), that would be
exponential growth - where speed multiplies by the same factor each second.
Why exponential doesn't match "constant rate":Let's test: If v0 =
5 and speed multiplies by
1.15 each second:
- After 1 sec:
5 ×
1.15 =
5.75 (increase of
0.75)
- After 2 sec:
5.75 ×
1.15 =
6.61 (increase of
0.86)
- After 3 sec:
6.61 ×
1.15 =
7.60 (increase of
0.99)
Notice: the increase keeps getting
larger each second (
0.75 →
0.86 →
0.99). That's NOT a constant rate - the rate itself is growing!
The correct interpretation:"Constant rate of increase" = same
amount added each second =
linear/arithmetic growthThis is why we use: v10 = v0 + (acceleration ×
10)
And for distance with constant acceleration:
Distance = Average Speed × Time = (v0 + v10)/
2 ×
10 =
125This gives us: v0 + v10 =
25Answer: v0 = 5, v10 = 20heeeya
Thanks for the helpful adive.
But I wonder why the speed at 2nd sec is V0+d not V0 x r when it is said to increase at a 'rate'.
Doesn't it meant that V1/V0 = V2/V1?