Energy transfer question (Use PE=KE or SUVAT ?)

In summary, the question asks for the velocity of an object that falls from a tree which is 3m above the ground. The answer can be found by either using the equation mgΔh=1/2mv2 or s=vt-1/2at2, with the condition that initial velocity (U) is equal to 0. When using the first equation, the answer is V=7.66ms-1, while using the second equation gives an answer of 17.15ms-1. However, upon further calculation, it is found that both methods give the same answer.
  • #1
CannonSLX
40
0

Homework Statement


Object falls from a tree which is 3m above the ground, what is its velocity when it hits the ground ?

Homework Equations


mgΔh=1/2mv2
or
s=vt-1/2at2

The Attempt at a Solution


Using the idea of PE=KE, as the masses cancel out I get an answer of V=7.66ms-1
However I thought that this question can also be done with a suvat equation, I use the same condition which is used for KE [That U=0].

When attempting with suvat I get an answer of 17.15ms-1 why is that ?
 
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  • #2
CannonSLX said:
When attempting with suvat I get an answer of 17.15ms-1 why is that ?

Hard to tell if you don't show your work!
 
  • #3
gneill said:
Hard to tell if you don't show your work!
Sorry, I just wanted to know if it was actually possible to be done using suvat ?
 
  • #4
CannonSLX said:
Sorry, I just wanted to know if it was actually possible to be done using suvat ?
Sure. And the answer should be the same :smile:
 
  • #5
gneill said:
Sure. And the answer should be the same :smile:
I just tried it again and looked like I forgot how to use my calculator o0), but I did get the same.

Thanks for confirming anyways :)
 

Related to Energy transfer question (Use PE=KE or SUVAT ?)

1. What is the difference between potential energy and kinetic energy?

Potential energy is the energy an object possesses due to its position or state, while kinetic energy is the energy an object possesses due to its motion. In other words, potential energy is stored energy, while kinetic energy is energy in motion.

2. Can potential energy be converted into kinetic energy?

Yes, potential energy can be converted into kinetic energy. This is known as energy transfer, where the stored energy in an object is transformed into energy of motion.

3. How do you calculate potential energy using the equation PE=mgh?

To calculate potential energy (PE) using the equation PE=mgh, you will need to know the mass (m) of the object, the acceleration due to gravity (g), and the height (h) of the object. Multiply the mass by the acceleration due to gravity and the height to get the potential energy in joules (J).

4. What is SUVAT and how is it related to energy transfer?

SUVAT is a set of kinematic equations that describe the motion of an object in terms of its initial velocity (U), final velocity (V), acceleration (A), time (T), and displacement (S). These equations can be used to determine the amount of energy transfer that occurs during an object's motion.

5. Can energy transfer occur without any change in potential or kinetic energy?

No, energy transfer always involves a change in potential or kinetic energy. For example, if an object falls from a height, its potential energy decreases while its kinetic energy increases. Energy cannot be created or destroyed, only transferred from one form to another.

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