Question

A particle moves on a line with a constant acceleration of 4ft/second. Find its equation of motion if s=2ft and v=-ft/sec, when t=2sec

Answer 1

Newton motion second law

$s=ut+\frac{1}{2}at^2$

$2=4\times2+\frac{1}{2}\times a\times2^2$

Solve it

$2-8=\frac{1}{2}a\times2^2$

$-6\times2=2^2a$

$a=-3ft/sec^2$

Where

$v=4ft/sec$

$s=2ft\\u=4ft/sec\\a=-3ft/sec^2$