An object is thrown straight up. How do we compare the net force on the object to its weight when it is at the highest point in the path?

Understanding the Situation

When an object is thrown straight up, it moves against the force of gravity until it reaches its maximum height (the highest point). At this point, it's essential to analyze the forces acting on the object.

Forces Acting on the Object

1. Weight (Force of Gravity): This is the force pulling the object downward. It is given by the formula: $F_{\text{weight}} = m \cdot g$ where $m$ is the mass of the object and $g$ is the acceleration due to gravity (approximately $9.81 \, \text{m/s}^2$ on the surface of the Earth).

2. Net Force: The net force on the object at the highest point can be derived from Newton's second law, which states that the net force is the mass times the acceleration (which is zero at the highest point because the object momentarily stops).

Analysis at the Highest Point

1. At the highest point of its path, the object has reached its maximum height and is about to start descending.
2. At this moment, the object's velocity is zero, but it is still under the influence of gravitational force.

Comparison of Forces

• As the object reaches its highest point:
  • The net force acting on the object is zero since it is momentarily at rest (before starting to fall).
  • However, the weight of the object is still acting downwards.

Therefore, we can conclude that:

• Net Force = 0 (the object is momentarily at rest)
• Weight (Downward) is still acting, which is not balanced by any upward force.

Final Answer

At the highest point in its path, the net force on the object is zero, while the weight of the object (gravitational force) is acting downward. This means that there is no upward force to counteract the weight, leading to a transition from upward to downward motion.