A visitor to the observation deck of a skyscraper manages to drop a penny over the edge. As the penny falls faster, the force due to air resistance increases. How does this affect the acceleration of the penny?
a. The acceleration decreases
b. The acceleration remains constant and not zero (my answer)
c. The acceleration remains zero
d. The acceleration increases.
if the force increases (more upward) the the net downward force must decrease.
So, (a) since F=ma
google terminal velocity
The correct answer is a. The acceleration decreases.
As the penny falls, the force exerted by the air resistance increases. Air resistance is a force that opposes the motion of an object through the air. When the penny first begins to fall, the force of gravity is greater than the force of air resistance, resulting in a net force downward and causing an initial acceleration.
However, as the penny picks up speed and falls faster, the force of air resistance becomes stronger. At some point, the force of air resistance will become equal to the force of gravity, resulting in a net force of zero. At this point, the penny will be moving at a constant speed, and its acceleration will be zero.
Therefore, as the air resistance increases, the net force on the penny decreases, leading to a decrease in acceleration.
To determine how air resistance affects the acceleration of the penny, we need to consider the forces acting on the penny.
When the penny is dropped from the observation deck, two main forces are at play – gravity and air resistance. The force of gravity is pulling the penny downward, while air resistance is pushing against the penny in the opposite direction. Initially, when the penny is stationary, the force of gravity is greater than the force of air resistance, causing the penny to start accelerating downwards.
As the penny falls faster and gains speed, the force of air resistance increases. At some point, the force of air resistance becomes equal to the force of gravity, creating a net force of zero. At this stage, the penny reaches a constant speed called the terminal velocity.
Now, let's consider how this affects the acceleration of the penny:
- Initially, when the force of gravity is greater than the force of air resistance, the acceleration of the penny is positive because the net force is downwards.
- As the force of air resistance increases and becomes equal to the force of gravity, the net force becomes zero. At this point, the acceleration of the penny becomes zero.
- Since the question is asking about how air resistance affects the acceleration, we can conclude that the correct answer is c. The acceleration remains zero.
Hence, option c is the correct answer.