Question

An object is dropped from a height and touched the ground with a velocity 100m/sec?if small gravitation=10m/sec2 find the height from which it is dropped and time taken to reach the ground​

Answer 1

Given :

➛ Initial velocity = zero

(i.e., free fall)

➛ Final velocity = 100m/s

➛ Acc. due to gravity = 10m/s²

To Find :

➝ Height from which object is dropped.

➝ Time taken by object to reach at the ground.

Solution :

➳ For a body, Falling freely under the effect of gravity, g is taken positive.

◈ Calculation of Height :

⇒ v² - u² = 2gH

⇒ (100)² - (0)² = 2×10×H

⇒ H = 10000/20

⇒ H = 500m

◈ Calculation of time :

⇒ v = u + gt

⇒ 100 = 0 + 10t

⇒ t = 100/10

⇒ t = 10s

Answer 2

$\huge\sf\pink{Answer}$

☞ Height = 50 m

☞ Time = 10 sec

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$\huge\sf\blue{Given}$

✭ Final Velocity= 100 m/s

✭ Acceleration = 10 m/s

✭ Initial Velocity = 0 m/s

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$\huge\sf\gray{To \:Find}$

◈ The height from which it is dropped?

◈ Time taken to reach the ground?

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$\huge\sf\purple{Steps}$

Here we shall use the 3rd Equation of motion,that is,

$\underline{\boxed{\sf v^2-u^2 = 2as}}$

Substituting the given values,

➝ $\sf 100^2 - 0^2 = 2(10)(s)$

➝ $\sf 10000 = 20s$

➝ $\sf \dfrac{10000}{20} = s$

➝ $\sf\orange{s = 500 \ m}$

Next to find the time we shall use the first Equation of motion, that is,

$\underline{\boxed{\sf v=u+at}}$

➢ $\sf 100 = 0+10\times t$

➢ $\sf 100=10t$

➢ $\sf \dfrac{100}{10} = t$

➢ $\sf\red{t = 10 \ s}$

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