Which are exhibiting kinetic energy?
The correct answer and explanation is :
Kinetic energy is the energy possessed by an object due to its motion. The formula for kinetic energy is:
$$
KE = \frac{1}{2} mv^2
$$
Where:
- $KE$ is kinetic energy,
- $m$ is the mass of the object, and
- $v$ is the velocity (speed) of the object.
Now, when determining which objects are exhibiting kinetic energy, we should focus on objects in motion. Here are some examples:
- A moving car: A car in motion has kinetic energy. The faster it moves, the more kinetic energy it has. The mass of the car also contributes to the total kinetic energy.
- A flying bird: The bird, as it flaps its wings and moves through the air, is exhibiting kinetic energy. Its speed and mass determine how much kinetic energy it has.
- A rolling ball: A ball rolling down a slope has kinetic energy because it is moving. The speed of the ball increases as it rolls, meaning its kinetic energy increases too.
- A falling rock: A rock falling freely due to gravity has kinetic energy. As it accelerates downward, its velocity increases, and so does its kinetic energy.
- A flowing river: The water in a river flows continuously, and its movement constitutes kinetic energy. The larger the flow rate and the faster the water moves, the more kinetic energy the river has.
Objects that are not exhibiting kinetic energy are those that are at rest or not in motion. For example:
- A stationary car, which is not moving, has zero kinetic energy.
- A resting bird on a branch or a rock lying still on the ground also has no kinetic energy because they are not moving.
In summary, kinetic energy is directly related to an object’s motion. Any object that is moving—whether it’s a car, bird, ball, or water—has kinetic energy. The amount of kinetic energy depends on the object’s mass and velocity. The faster an object moves and the greater its mass, the more kinetic energy it will have.