If the uniform acceleration near the surface of the earth is about 9.8 `m//sec^2`. for a free-fall, what Is the velocity at the end of 2 seconds of fall (neglect friction) ?

A. 14.6 m/sec
B. 17.0 m/sec
C. 19.6 m/sec
D. 9.8 m/sec.

Options

A. 14.6 m/sec
B. 17.0 m/sec
C. 19.6 m/sec
D. 9.8 m/sec.

Explanation

To solve the problem of finding the velocity of an object in free fall after 2 seconds, we can use the first equation of motion, which relates initial velocity, acceleration, time, and final velocity. Here’s the step-by-step solution:

### Step 1: Identify the given values
- Initial velocity (u) = 0 m/s (the object is at rest initially)
- Acceleration (a) = 9.8 m/s² (acceleration due to gravity)
- Time (t) = 2 seconds

### Step 2: Use the first equation of motion
The first equation of motion states:
\[ v = u + a \cdot t \]
where:
- \( v \) is the final velocity,
- \( u \) is the initial velocity,
- \( a \) is the acceleration,
- \( t \) is the time.

### Step 3: Substitute the known values into the equation
Substituting the values we have:
\[ v = 0 + (9.8 \, \text{m/s}^2) \cdot (2 \, \text{s}) \]

### Step 4: Calculate the final velocity
Now, perform the multiplication:
\[ v = 9.8 \, \text{m/s}^2 \cdot 2 \, \text{s} = 19.6 \, \text{m/s} \]

### Step 5: State the final answer
The final velocity of the object at the end of 2 seconds of free fall is:
\[ v = 19.6 \, \text{m/s} \]

### Conclusion
The correct answer is option C: 19.6 m/s.

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