Question

a particle starts from a point with velocity of 6 m per second and moves with an acceleration -2m per second. squared. show that after 6 seconds the particle will be at starting point.

Answer 1

u=6m/sec
a= -2m/s squared
t=6sec
v=u+at
=6+(-2)6
6-12
-6
hence v=6m/sec i.e, after 6 seconds the particle will be at the starting point i.e, at u=6m/s

Answer 2

Given:

1. u = 6 m/s

2. a = (-2) m/s

3. t = 6 s

v = u + at {First Equation of Motion}

v = 6 + (-2)(6)

v = 6 - 12

∴ v = (-6) m/s

v² - u² = 2as {Third Equation of Motion}

(-6)² - 6² = 2(-2)s

36 - 36 = (-4)s

$\frac{0}{4}$ = s

∴ s = 0

Hence Proved!