Which object has kinetic energy?
a
a person running on the sidewalk
b
a bird perched in a tree
c
a ball sitting under a table
d
a person standing at the top of stairs
The object that has kinetic energy is a person running on the sidewalk (option a).
The object that has kinetic energy is:
a) A person running on the sidewalk.
To determine which object has kinetic energy, we need to understand what kinetic energy is. Kinetic energy is the energy possessed by an object due to its motion. It depends on both the mass and the velocity of the object.
Let's analyze each scenario:
a) A person running on the sidewalk: This person is in motion, so they have kinetic energy. Their mass and velocity contribute to the amount of kinetic energy.
b) A bird perched in a tree: A perched bird is not in motion, so it does not have kinetic energy. However, it may have potential energy due to its position.
c) A ball sitting under a table: The ball is at rest, not in motion. Therefore, it does not have kinetic energy at that moment.
d) A person standing at the top of stairs: This person is not in motion, so they do not have kinetic energy. However, just like the bird, they may have potential energy due to their position.
Based on this analysis, the correct answer is (a) a person running on the sidewalk, as they are in motion and possess kinetic energy.