Question

A pebble thrown vertically upwards with an initial velocity 50ms^-1 comes to a stop in 5s Find the retardation

Answer 1

Answer:

initial vel. 50ms(u)

final vel. 0ms(v)

retardation. u-v/t

=50-0/5

=50/5

=10

therefore, retardation is 10m/s2

Answer 2

Given Initial velocity u = $\rm 50m {s}^{ - 1}$

Final velocity v = 0

Time t = 5s

$\rm \: Acceleration \: a= \frac{v - u}{t} = \frac{0 - 50m {s}^{ - 1} }{5s}$

$\rm \: Acceleration=-10m {s}^{ - 2}$

$\fbox{ \rm \: retardation = {10ms}^{ - 2} }$

(since retardation is negative of acceleration)