Question

A ball is falling freely from a certain height. It reaches ground after 3 second. If 30 m/s is the velocity of the ball while touching the ground then.

a) What is the initial velocity of the ball? b) What is the final velocity of the ball?

c) Calculate its acceleration?

d) Determine whether the motion is retardation or not.​

Answer 1

a) initial velocity is 0m/s
b)final velocity is 30m/s
c) accln = v-u/t
30-0/3
=30/3
=10 m/s -2
d) the motion is not retardation because accln is 10 m/s -2

Answer 2

QUESTION:

A ball is falling freely from a certain height. It reaches ground after 3 second. If 30 m/s is the velocity of the ball while touching the ground then:-

a) What is the initial velocity of the ball?

b) What is the final velocity of the ball?

c) Calculate its acceleration?

d) Determine whether the motion is retardation or not.

Solution:

a) initial velocity = 0 m/s

(b) final velocity = 30 m/s (given in question)

(c) To find acceleration use Formula :

$v \: = u + at$

where:-

• v = final velocity
• u = initial velocity
• a= acceleration
• t= time

therefore put :-

• v = 30
• u = 0
• t = 3

$30= 0 + (a \times 3)$

$30= 3a$

$\frac{30}{3} = a$

$a = 10$

Therefore acceleration is 10m/s²

(d) Now since acceleration is positive therefore motion is not retardation.

__________________________

Learn more :-

v= u+at

v²-u²= 2as

s = ut+1/2at²

RETARDATION :-

Retardation is negative acceleration. If the velocity of the body increases, acceleration is positive. if the velocity decreases, the acceleration is negative.