Question

10.
An object moving with a velocity of 30 m/s decelerate at the rate of 1.5 of m/s2. Find the time taken by the object to
come to rest
​

Answer 1

$\sf\small\underline\blue{Given:-}$

• Initial velocity ,u = 30m/s
• Final velocity ,v = 0m/s (come to rest)
• Acceleration, a = -1.5m/s² (in opposite direction)

$\sf\small\underline\green{To Find:-}$

• Time taken by the object to come to rest ,t

$\sf\small\underline\pink{Answer:-}$

According to the Question

It is given that the object start with velocity of 30m/s decelerate at the rate of 1.5m/s² and come to rest .

We have to calculate the time taken by the object to come to rest. Using 1st equation of motion

• v = u +at

where,

• v is the final velocity
• a is the acceleration
• u is the initial velocity
• t is the time taken

Substitute the value we get

$:\implies$ 0 = 30 + (-1.5) ×t

$:\implies$ -30 = -1.5×t

$:\implies$ 30 = 1.5×t

$:\implies$ 1.5 × t = 30

$:\implies$ t = 30/1.5

$:\implies$ t = 300/15

$:\implies$ t = 20 s

• Hence, the time taken by the object to come to rest is 20 seconds.

Answer 2

Answer:

Given :-

An object moving with a velocity of 30 m/s decelerate at the rate of 1.5 of m/s²

To Find :-

Time taken

Solution :-

We know that

v = u + at

0 = 30 + [-1.5(t)]

0 - 30 = -1.5(t)

-30 = -1.5t

-30/-1.5 = t

30/1.5 = t

20 = t

Hence,

Time taken is 20 seconds