Can Kinetic Energy be Generated without Initial Speed?

In summary: However, in this case, the problem statement specifically mentions that there is a force that is not constant. If you can solve a problem without having to consider forces, that might be within your syllabus. However, in this case, the problem statement specifically mentions that there is a force that is not constant.
  • #1
sgstudent
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3

Homework Statement


Is it possible to have a scenario like this. An object is pushed up a slope and it has no initial speed. When it reaches the top the object's speed is also zero. So it's like work done by push+work done against friction=mgh. It doesn't seem plausible to me.

Homework Equations


Work done=force X distance moved in the direction of force


The Attempt at a Solution


I don't think it's possible as the object has 0 kinetic energy at the end. That means that the applied force can only counter the friction so it shouldn't be able to start moving at all unless it initially has speed already then it would be work done by push+work done against friction+KE=KE+mgh in this case even though numerically is the same it is different as now when there is no net force the object still has velocity so by Newton's first law it will continue to move up to the top with a constant speed.

The only possible way when the object has no velocity at first is if there is kinetic energy at the end because this means that the object accelerated which means there is net force acting on the object which makes it plausible for it to move.

Are these correct? Thanks for the help!
 
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  • #2
The acceleration doesn't have to be constant. The object may start at rest, be pushed up the slope, and allowed to come to rest again.
work done by push+work done against friction=mgh
No. Try that again.
 
  • #3
haruspex said:
The acceleration doesn't have to be constant. The object may start at rest, be pushed up the slope, and allowed to come to rest again.

No. Try that again.

but if we look at a constant force then that's not possible right? Since if we just look at the forces acting on the object, the object experiences no net force.
 
  • #4
sgstudent said:
but if we look at a constant force then that's not possible right? Since if we just look at the forces acting on the object, the object experiences no net force.
If the force were constant it would not be possible since the object would keep moving faster. But your problem statement doesn't say it's constant.
 
  • #5
haruspex said:
If the force were constant it would not be possible since the object would keep moving faster. But your problem statement doesn't say it's constant.

Oh sorry I forgot to say I was taking O level so we deal with constant forces only. Thanks
 
  • #6
sgstudent said:
Oh sorry I forgot to say I was taking O level so we deal with constant forces only. Thanks
I accept that you are only expected to deal with forces that are constant, but that's not quite the same as only dealing with problems in which all forces are constant. If you can solve a problem without having to consider forces, that might be within your syllabus.
 

FAQ: Can Kinetic Energy be Generated without Initial Speed?

Can kinetic energy be generated without any initial speed?

Yes, kinetic energy can be generated without any initial speed. This is known as potential energy, which is stored energy that has the potential to be converted into kinetic energy when it is released.

How is kinetic energy generated without initial speed?

Kinetic energy can be generated without initial speed through various means such as chemical reactions, nuclear reactions, and gravitational potential energy. For example, when a ball is held at a certain height, it has potential energy. When it is released, it converts into kinetic energy as it falls.

Is it possible to convert potential energy into kinetic energy without any initial speed?

Yes, it is possible to convert potential energy into kinetic energy without any initial speed. This can happen when an object is acted upon by an external force, such as gravity or an explosion. The potential energy is converted into kinetic energy as the object moves.

Can kinetic energy be generated without any external force?

No, kinetic energy cannot be generated without any external force. The first law of thermodynamics states that energy cannot be created or destroyed, it can only be converted from one form to another. In the case of kinetic energy, it is converted from potential energy or another form of energy through an external force.

Can kinetic energy be generated without any movement?

No, kinetic energy is the energy of motion, so it cannot be generated without any movement. However, an object can have potential energy without any movement, and when released, it can convert into kinetic energy as it begins to move.

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