Question

$friends \: read \: it \:you \: have \: time$
what is stephen hawking​

Answer 1

it's a name...........

Answer 2

Answer:

Answer:

Given :-

A body moving with velocity 40 m/s is brought to rest in 20 seconds.

To Find :-

What is the retardation and the distance travelled by a body.

Formula Used :-

❶To find acceleration we know that,

\boxed{\bold{\large{v\: =\: u\: +\: at}}}

v=u+at

❷ To find distance travelled we know that,

\boxed{\bold{\large{{v}^{2} =\: {u}^{2} +\: 2as}}}

v

2

=u

2

+2as

where,

v = Final velocity

u = Initial velocity

a = Acceleration

t = Time

s = Distance travelled

Solution :-

❶ To find retardation,

Given :

Final velocity = 0 m/s

Initial velocity = 40 m/s

Time = 20 seconds

According to the question by using the formula we get,

⇒ 0 = 40 + a(20)

⇒ 0 - 40 = 20a

⇒ - 40 = 20a

⇒ \dfrac{\cancel{- 40}}{\cancel{20}}

20

−40

= a

⇒ - 2 = a

➠ a = - 2 m/s²

\therefore∴ The retardation of a body is - 2 m/s² .

❷ To find distance travelled,

Given :

Final velocity = 0 m/s

Initial velocity = 40 m/s

Time = 20 seconds

Acceleration = - 2 m/s²

According to the question by using the formula we get,

↦ (0)² = (40)² + 2(- 2) × s

↦ 0 = 1600 - 4 × s

↦ 0 = 1600 - 4s

↦ 0 - 1600 = - 4s

↦ - 1600 = - 4s

↦ \dfrac{\cancel{- 1600}}{\cancel{- 4}}

−4

−1600

= s

↦ 400 = s

➥ s = 400 m

\therefore∴ The distance travelled by a body is 400 m .