I'm having an issue with two similar questions
1. A particle with uniform acceleration of 4ms-2 and covers 38 m over its fifth second of motion. Using its avarage velocity in this time period find the initial velocity.
2. A body moves with uniform acceleration. It travles 8.5m in the eight second and 7.5 m during the thirteenth second of it's motion. Using the average velocity from this time, find the initial velocity and acceleration.
Acceleration over this time using v=u+at v = 7.5 u = 8.5 t = 5
a = -0.2
1.OK.....what is the average velocity?
It covered 38 m in 0.2 sec
Uh-ohh....your question is unclear in its wording
in second # 5 did i cover 38 m or did it cover 38 m in 1/5 sec ????
I will go with the former (though that is not what I initially thought)
vf = vo + at = 38 = vo + (4)(5)
38 = vo + (20)
18m/s = vo
2. vf = vo + at = 7.5 = 8.5 + a(5)
-1 = a 5
- .2 = a OK so we know the accel is negative 0.2 (it is DEccelerating....slowing down)
vf = vo + at
8.5 = vo + (-0.2)(8)
8.5 = vo - 1.6
10.1 m/s = vo
(ALWAYS remember the UNITS)