Question

We use an apostrophe followed by an
's' to show that something belongs to
someone.​

Answer 1

Answer:

Question:-

A body is allowed to fall from a tower 320 m high. When the ball reaches half the way acceleration due to gravity suddenly disappears. The velocity of the body after two seconds is (g = 10 m/s).

To Find:-

Find the velocity of the body.

Solution:-

Given ,

A body is allowed to fall from a tower 320 m high.

If reaches half its distance 320/2 = 160 m.

First ,

We have to find the time travelled in half distance:-

\dashrightarrow\sf \: s = ut + \dfrac { 1 } { 2 } { at }^{ 2 }⇢s=ut+

2

1

at

2

\dashrightarrow\sf \: 160 = \dfrac { 1 } { 2 } \times 10 \times { t }^{ 2 }⇢160=

2

1

×10×t

2

\dashrightarrow\sf \: 160 = 5 { t }^{ 2 }⇢160=5t

2

\dashrightarrow\sf \: { t }^{ 2 } = \dfrac { 160 } { 5 }⇢t

2

=

5

160

\dashrightarrow\sf \: t = \sqrt { 32 } \: seconds⇢t=

32

seconds

How ,

We have to find the final velocity:-

\dashrightarrow\sf \: v = u + at⇢v=u+at

\dashrightarrow\sf \: v = 0 + 10 \sqrt { 32 }⇢v=0+10

32

\dashrightarrow\sf \: v = 10 \sqrt { 32 } \: m/s⇢v=10

32

m/s

Now ,

We have to find the velocity after 2 seconds:-

\dashrightarrow\sf \: ( \sqrt { 32 } + 2 ) \: seconds = 10 \sqrt { 32 }⇢(

32

+2)seconds=10

32

\dashrightarrow\sf \: 56 \: m/s⇢56m/s

Hence ,

Velocity after 2 seconds is 56 m/s