The acceleration of a body projected upwards with a certain velocity is

Options

A. 9.8 `m/s^(2)`
B. `-9.8 m/s^(2)`
C. zero
D. insufficient data

Answer

To solve the question regarding the acceleration of a body projected upwards with a certain velocity, we can follow these steps:

### Step 1: Identify the forces acting on the body
When a body is projected upwards, the only significant force acting on it (in the absence of air resistance) is the force of gravity. This force can be expressed as:
\[ F = mg \]
where \( m \) is the mass of the body and \( g \) is the acceleration due to gravity.

### Step 2: Understand the direction of acceleration
The acceleration due to gravity acts downwards towards the center of the Earth. Therefore, even though the body is moving upwards, the acceleration due to gravity will act in the opposite direction to the velocity of the body.

### Step 3: Determine the value of gravitational acceleration
The standard value of gravitational acceleration \( g \) near the surface of the Earth is approximately:
\[ g \approx 9.8 \, \text{m/s}^2 \]

### Step 4: Assign the direction of acceleration
Since the body is moving upwards and the force of gravity is acting downwards, the acceleration will be negative with respect to the upward motion. Thus, we can express the acceleration as:
\[ a = -g \]

### Step 5: Substitute the value of \( g \)
By substituting the value of \( g \) into the equation, we get:
\[ a = -9.8 \, \text{m/s}^2 \]

### Final Answer
The acceleration of the body projected upwards is:
\[ a = -9.8 \, \text{m/s}^2 \]

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