Question

A body of mass 10 kg is dropped from a height of 32 m. Find its: (take g= 10 m/s²)

a) initial potential energy at this height

b) kinetic energy when it reaches the ground

c) velocity when it is half way down.
answer fast pls​

Answer 1

Answer:

a) initial potential energy at this height

b) kinetic energy when it reaches the ground

c) velocity when it is half way down.

Answer 2

$\underline{\underline{\purple{\textbf{Step - By - Step - Explanation : -}}}}$

To Find :

• a) initial potential energy at this height
• b) kinetic energy when it reaches the ground .
• c) velocity when it is half way down.

Solution :

• mass of body = 10kg
• height = 32m
• g = 10m/s²

(a) Initial potential energy at the same height.

As we know that,

$\boxed{\underline{\red{\textrm{Potential Energy = mgh}}}}$

where,

• m = mass
• g = acceleration due to gravity
• h = height

Potential Energy = m × g × h

= 10 × 10 × 32

= 100 × 32

= 3200J

$\green{\textrm{Potential Energy = 3200 Joules}}$

b) kinetic energy when it reaches the ground .

By using third Equation of motion

• v² = u² + 2gh

v² = 0 + 2 × 10 × 32

v² = 64 × 10

v² = 640

v = √640

v = 8√10

$\boxed{\underline{\red{\bf{Kinetic \:Energy =\frac{1}{2}mv^{2}}}}}$

= 1/2 × 10 × (8√10)²

= 5 × 64 × 10

= 5 × 640

= 3200J

$\orange{\textrm{Kinetic Energy of body = 3200 joules}}$

c) velocity when it is half way down.

velocity of body = 8√10

• velocity when it is half way down

= 8√10/2

= 4 √10

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