Potential energy loss related to force applied?

In summary, it is not possible to directly calculate the energy loss based on the force applied over time in a system where there is no motion. This is because if no work is done, there is no mechanical energy loss. The energy loss in this case would be due to the resistance of the wires and the internal resistance of the power source, which can be measured with electrical meters. Therefore, there is no equation that relates potential energy loss to an integral of force and time.
  • #1
Joey Wilson
5
0
How can I calculate the loss of potential energy when forces are applied but no motion in the system occurs? Here's an example:

Let's say I build a battery operated car that is set to drive forward, but I put it right in front of a wall. It attempts to drive forward, but instead it just pushes into the wall and nothing moves. The battery will continue to drain, and thus potential energy is being lost, yet no work is happening. The car and the wall do not move. Let's assume that the car is able to push the wall with a consistent force of 1 Newton.

If I know how long the car has been pushing (let's say for one hour), can I calculate the potential energy loss based on the fact that the car has been pushing with 1 Newton, for one hour? The work is zero because if W=fd, the distance is 0, so the work is zero. Yet, there definitely is a loss of potential energy in the battery. How can I calculate that?
 
Physics news on Phys.org
  • #2
If there is no motion, then all the energy loss of the battery goes into heating the coils in the motor. You can calculate that if you know the current ##I## that the stalled motor draws. Then ##E = IVt## where ##V## is the battery voltage and t = 3600 s. That's assuming that the battery voltage stays constant and the motor doesn't burn out.
 
  • #3
kuruman said:
If there is no motion, then all the energy loss of the battery goes into heating the coils in the motor. You can calculate that if you know the current ##I## that the stalled motor draws. Then ##E = IVt## where ##V## is the battery voltage and t = 3600 s. That's assuming that the battery voltage stays constant and the motor doesn't burn out.

Thank you for the reply. I'm wondering if there is a way to directly calculate the energy loss based on the force applied over time, rather than calculating from internal workings. The reason is we can measure the force applied over time, but measuring the internal flows is not possible.
 
  • #4
Joey Wilson said:
energy loss based on the force applied
If no work is done (no motion) then there is no mechanical "energy loss". A Force X Zero Distance involves No Work. When a motor is stalled, there is no back emf to restrict the current through the armature and energy is lost only in the resistance of the wires - and, of course, in the Power source (internal resistance of a battery for instance). The lost Power has to be measured with electrical meters.
 
  • #5
sophiecentaur said:
If no work is done (no motion) then there is no mechanical "energy loss". A Force X Zero Distance involves No Work. When a motor is stalled, there is no back emf to restrict the current through the armature and energy is lost only in the resistance of the wires - and, of course, in the Power source (internal resistance of a battery for instance). The lost Power has to be measured with electrical meters.

OK - so you're saying there is no equation that relates potential energy loss to an integral of force and time?
 
  • #6
Joey Wilson said:
OK - so you're saying there is no equation that relates potential energy loss to an integral of force and time?
That is correct. ∫Fdt is impulse which is equal to change in momentum. If nothing is moving, there is no change in momentum. Besides, impulse and energy have different dimensions.
 
  • Like
Likes sophiecentaur

Related to Potential energy loss related to force applied?

What is potential energy loss?

Potential energy loss is the decrease in stored energy that occurs when a force is applied to an object. This can happen in various forms, such as mechanical potential energy being converted into kinetic energy or thermal energy.

How is potential energy loss related to force applied?

Potential energy loss is directly related to the force applied to an object. The greater the force applied, the greater the potential energy loss. This is because a larger force causes more work to be done on the object, resulting in a greater decrease in stored energy.

What factors affect potential energy loss?

There are several factors that can affect potential energy loss, including the type of force applied, the distance over which the force is applied, and the mass and initial potential energy of the object. Additionally, factors such as friction and air resistance can also impact potential energy loss.

How can potential energy loss be minimized?

Potential energy loss can be minimized by reducing the amount of force applied to an object or by increasing the distance over which the force is applied. Additionally, minimizing factors such as friction and air resistance can also help to reduce potential energy loss.

What are some real-life examples of potential energy loss?

Some common examples of potential energy loss include a ball rolling down a hill, a car braking to come to a stop, and a pendulum swinging back and forth. In each of these cases, potential energy is converted into other forms, such as kinetic energy or thermal energy, resulting in a decrease in stored energy.

Similar threads

Replies
16
Views
1K
Replies
4
Views
1K
Replies
9
Views
2K
Replies
12
Views
890
Replies
10
Views
1K
Replies
13
Views
1K
Replies
14
Views
959
Replies
5
Views
818
Back
Top