Question

What will be the kinetic energy of a 100 gram mass object 3 seconds after it starts falling unhindered from a height of 500 meters?

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Answer 1

Answer:

Given -

• Mass, m = 100 g = 0.1 kg
• Time, t = 3 sec
• Height, h = 500 m

To find-

• Kinetic energy of the object.

Solution -

For kinetic energy, firstly we need to find the velocity of the object.

Let's v be the velocity -

$\\ \large{ \boxed{ \sf{v = gt}}} \\ \\ \\ \implies \sf \: v = 10 \times 3 \qquad \quad \: \: \: \: \: ( \: g = 10) \\ \\ \\ \implies \sf{ \underline {\: 30 \: m/s}}$

Therefore, the velocity is 30 m/s.

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$\\ \large{ \underline{ \mathfrak{ \star \: Kinetic \: \: energy \: - }}} \\ \\ \\ \implies \sf \: \dfrac{1}{2} \: {mv}^{2} \\ \\ \\ \footnotesize{ \underline{ \sf{substituting \: \: the \: \: given \: \: values \: - }}} \\ \\ \\ \implies \sf \: K.E \: = \frac{1}{2} \times 0.1 \times 30 \times 30 \\ \\ \\ \implies \sf \: K.E = 1 \times 0.1 \times \: 450 \\ \\ \\ \implies \sf{ \blue{K.E \: = 45 \: J}}$

Therefore, the kinetic energy of the object is 45 J.