Question

A ball is thrown vertically upward and it's reaches a height of 90m find the velocity with it was thrown and also the height by the ball 7 second after it was thrown

Answer 1

Answer:

Therefore, at maximum altitude the velocity of the ball must be zero. Question: A ball thrown vertically upward reaches a maximum height of 30 meters above the surface of Earth. At its maximum height, the speed of the ball is: Answer: 0 m/s.

Answer 2

Given Info :-

• A ball is thrown vertically upward and it reaches a maximum height of 90 m.Where g is equal 9.8 m/s².

Explanation :-

We are asked to find out –

• The velocity with which it was thrown
• The height reached by the ball after 7s.

We know that –

$\purple{\bigstar \; {\underline{\boxed{\bf{ Maximum \: Height =\dfrac{u² }{2g} }}}}}$    

$\longrightarrow \tt 90 \times 2g = u²$

$\longrightarrow \tt 180 \times 9.8 = u²$

$\longrightarrow \tt u² = 1764$

$\longrightarrow \tt{\pink{\underline{\underline u= 42\: m/s}}}$

• Hence, The velocity at which the ball was thrown was 42 m/s.

Now, we are given –

• u = 42 m/s
• t = 7 s

• The height achieved by the ball 7s after it was thrown will be –

$\purple{\bigstar \; {\underline{\boxed{\bf{ Height =ut -\dfrac{1}{2}gt² }}}}}$    

(Because 'g is acting in opposite direction of motion)

$\longrightarrow \tt H = 42 \times 7 - \dfrac{ 1}{2 }\times 9.8 \times 49$

$\longrightarrow \tt H = 294 - 240.1$

$\longrightarrow \tt{\pink{\underline{\underline H = 53.9\: m}}}$

• Hence,The height achieved by the ball 7s after it was thrown is 53.9 m.

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