Potential energy function is the energy possessed by the body by virtue of its position. Potential energy of a body is the energy possessed by the body by virtue of its velocity and is given by `1//2 mv^(2)`. Energy can neither be created nor be destroyed. However, energy can be changed from one form to the other, such that energy appearing in one form to the other, such that energy appearing in one form is equal to the energy disappearing in the other form.
Kinetic energy of the body 5 s after it starts falling is

Options

A. 1250J
B. 2500J
C. 625J
D. 25,000J

Answer

To find the kinetic energy of a body 5 seconds after it starts falling, we can follow these steps:

### Step 1: Understand the problem
We need to calculate the kinetic energy of a body after it has been falling for 5 seconds. The body is in free fall, so we can use the equations of motion under gravity.

### Step 2: Identify the initial conditions
- The initial velocity (u) of the body is 0 m/s (since it starts from rest).
- The acceleration (a) due to gravity is approximately \( g = 9.8 \, \text{m/s}^2 \).

### Step 3: Calculate the final velocity (v) after 5 seconds
Using the equation of motion:
\[ v = u + at \]
Substituting the values:
\[ v = 0 + (9.8 \, \text{m/s}^2)(5 \, \text{s}) \]
\[ v = 49 \, \text{m/s} \]

### Step 4: Calculate the kinetic energy (KE)
The formula for kinetic energy is:
\[ KE = \frac{1}{2} mv^2 \]
We need to know the mass (m) of the body to calculate the kinetic energy. However, since the mass is not given, we can express the kinetic energy in terms of mass:
\[ KE = \frac{1}{2} m (49)^2 \]
\[ KE = \frac{1}{2} m (2401) \]
\[ KE = 1200.5 m \, \text{Joules} \]

### Step 5: Conclusion
The kinetic energy of the body after 5 seconds of free fall is \( 1200.5 m \) Joules, where \( m \) is the mass of the body.

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