Question

A BODY OF MASS 0.2KG FALLS FROM A HEIGHT OF 10MTO HEIGHT OF 6M ABOVE THE GROUND .THE LOSS OF IN P.E IS GIVEN BY (TAKE G=10M/S^2)

Answer 1

Question

A body of mass 0.2 kg falls from a height of 10m to a height of 6m above the ground. The loss of P.E. (potential energy) is. [Given that G = 10 m/s² ]

Solution

A body of mass 0.2 kg falls from a height of 10 m.

Given that-

• Mass of body (m) = 0.2 kg
• Initial height (h1) = 10 m
• Acceleration due to gravity (g) = 10 m/s²

We know that,

$\underline{\boxed{\sf{P.E. \:= \:mgh}}}$

Let us assume that, initial height is h1 and final height is h2.

P.E. = mgh1

Substitute the known values

$\Rightarrow\:\sf{0.2 \times 10 \times 10}$

$\Rightarrow\:\sf{20J}$

Similarly, In the second case:

Given that-

• Final height (h2) = 6 m

(Mass and acceleration remains the same)

P.E'. = mgh2

Substitute the known values

$\Rightarrow\:\sf{0.2 \times 10 \times 6}$

$\Rightarrow\:\sf{12J}$

We have to find the loss in Potential energy. i.e.

$\underline{\boxed{\sf{ \triangle P.E. \:= \:P.E.-P.E.'}}}$

$\Rightarrow\:\sf{(20-12)J}$

$\Rightarrow\:\sf{8J \: { \bold{[Answer.]}}}$

Answer 2

Explanation:

Given -

• Mass of body 0.2 Kg fall from a height of 10 m to height of 6 m above the ground.

To Find -

Loss in Potential energy

As we know that :-

• P•E = mgh

Case I :-

Mass of body = 0.2 Kg

g = 10 m/s²

h¹ = 10 m

» mgh¹

» 0.2 × 10 × 10

• » 20 J

Case II :-

Mass of body = 0.2 Kg

g = 10 m/s²

h² = 6 m

» mgh²

» 0.2 × 10 × 6

• » 12 J

Now,

As we know that :-

• Loss in P•E = mgh¹ - mgh²

» 20 J - 12 J

• » 8 J

Hence,

The Loss in P•E is 8 J.