Question

Give an example for each of the following situations:

1) Negative acceleration, but positive velocity
2) Positive acceleration and positive velocity
3) Positive acceleration, but negative velocity
4) Negative acceleration and negative velocity
5) Positive velocity and no acceleration

Answer 1

Examples for each motion scenario have been provided utilizing a conventional coordinate system where rightward direction is positive. Negative acceleration paired with positive velocity is like a braking car, while positive acceleration can either speed up or slow down a car, depending on the direction of the car's initial velocity. A ball at its peak has zero velocity but experiences acceleration due to gravity.

Step-by-step explanation:

In physics, understanding velocity and acceleration as vector quantities is crucial to solving problems involving motion. Velocity is the speed with a direction, and acceleration is the rate of change of velocity with time. If a quantity is positive, it suggests a direction to the right, and negative implies a direction to the left, based on a conventional coordinate system.

Here are examples for each of the situations mentioned:

• Negative acceleration and positive velocity: A car moving to the right but slowing down because of braking.
• Positive acceleration and positive velocity: A car speeding up as it moves to the right.
• Positive acceleration but negative velocity: A car initially moving to the left but is slowing down, indicative of a positive acceleration toward the right.
• Negative acceleration and negative velocity: A car accelerating to the left, thus increasing its speed in the leftward direction.
• Positive velocity and no acceleration: A car cruising at constant speed to the right is not accelerating.

Additional examples:

• Velocity zero yet acceleration not zero: A ball thrown upwards has zero velocity at its peak, but it has a negative acceleration due to gravity.
• If a subway train moving to the left stops, its acceleration is positive because the change in velocity is directed to the right (opposite to the negative velocity).
• An airplane landing toward the east with negative acceleration indicates the acceleration is towards the west, hence it is decelerating.

Answer 2

1) Negative acceleration, but positive velocity

If a ball is thrown up then velocity is positive upwards while acceleration is downwards negative

2) Positive acceleration and positive velocity

If a car is moving towards positive direction with increasing speed due to which acceleration is also positive in it

3) Positive acceleration, but negative velocity

If a car is moving towards negative direction and car apply brakes due to which it will slow down then its acceleration must be positive

4) Negative acceleration and negative velocity

When a ball is falling downwards under the influence of gravity then velocity and acceleration both are positive

5) Positive velocity and no acceleration

If an object is moving with uniform speed towards Positive X direction without any acceleration or force