Question

A subway train starting from rest leaves a station with a constant acceleration. At the end of 7.25 s, it is moving at 17.3275 m/s.
What is the train’s displacement in the first 5.162 s of motion?
Answer in units of m

Answer 1

A subway train starting from rest leaves a station with a constant acceleration. At the end of 7.25 s, it is moving at 17.3275 m/s.

What is the train's displacement in the first 5.162 s of motion?

Answer in units of m

Solution:

Let:

$$v = 17.3275 \, \mathrm{m/s}$$ $$t(1) = 7.25 \, \mathrm{s}$$ $$t(2) = 5.162 \, \mathrm{s}$$

S-?

$S = \frac{1}{2} at(2)^2$, were a-acceleration of the train.

Such as $v = at(1)$

$$a = \frac{v}{t(1)}$$ $$S = \frac{1}{2} \frac{v}{t(1)} t(2)^2$$ $$S = \frac{1}{2} * \frac{17.3275}{7.25} * (5.162)^2 = 31,84226 \, \mathrm{m}$$