Question

Activity title: solving problems for uniformly accelerated rectilinear motion
learning target: to calculate displacement,velocity,acceleration and time using the four kinematic equations.

1. A french high-velocity train accelerated uniformly from 250km/hr to 300 km/hr as it sped through a distance of 50 km.finds its acceleration.

Answer 1

v² = u² + 2as
where v = final velocity
u = initial velocity
s = distance

here v = 300 km/h = 300,000 m/3600 s = 250/3 m/s
u = 250 km/h = 250,000 m/3600s = 625/9 m/s
s = 50 km = 50000 m

Answer 2

above equation can be rearranged as follows:
v² - u²
------ = a
2 s

( 250 )^2 ( 625 )^2 m^2
(------ ) - (------) -------
( 3 ) ( 9 ) s^2
----------------------------------- = a
2 * 50000 m

62500 390625 m^2
------ - -------- ------
9 81 s^2
-------------------------- = a
100000 m

562,500 - 390,625 m^2
------------------ ------
81 s^2
------------------------- = a
100,000 m

171,875 1 m^2
------- * ---------- --------- = a
81 100,000 s^2 * m

Answer 3

171,875 m
--------- ----- = a
8,100,000 s^2

so a = 0.02 m/s^2