A football is kicked into the air vertically upwards. What is its (a) acceleration, and (b) velocity at the highest point ?

Options

A. a. g b. u
B. a. `g//2` b. 2u
C. a. g b. zero
D. a. zero b.4u

Explanation

To solve the problem of a football kicked vertically upwards and to determine its acceleration and velocity at the highest point, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Motion**:
- When the football is kicked upwards, it moves against the force of gravity. The motion is vertical, and we need to consider the effects of gravity on the ball.

2. **Acceleration at the Highest Point**:
- The acceleration of the football is due to gravity, which acts downwards. This gravitational acceleration is approximately \( g = 9.81 \, \text{m/s}^2 \) (or can be approximated as \( 10 \, \text{m/s}^2 \) for simplicity).
- At the highest point of its trajectory, the acceleration due to gravity remains constant and is still \( g \) acting downwards.

3. **Velocity at the Highest Point**:
- As the football rises, it decelerates due to the gravitational force acting in the opposite direction to its motion.
- At the highest point, the upward velocity of the football becomes zero because it has momentarily stopped before it starts to fall back down.

4. **Conclusion**:
- Therefore, at the highest point:
- (a) The acceleration is \( g \) (downwards).
- (b) The velocity is \( 0 \, \text{m/s} \).

### Final Answer:
- (a) Acceleration = \( g \)
- (b) Velocity = \( 0 \, \text{m/s} \)