Dropping meat on weighing scale

In summary, when you drop a 1kg meat from 1m above the plate, the spring will compress more than when it reaches equilibrium (mg=kx). To find the initial compression, you can use conservation of energy and conservation of momentum.
  • #1
quietrain
655
2
hi, if we drop a piece of meat say 1kg from 1m above the plate, on a plate 2kg, and the plate is on a weighing scale of spring F=kx, how do we find how much the spring will first compress? ( not referring to the equilibrium where total weight = spring force)

so we can't use F=kx = mg here because the mg is for the piece of meat only, but how do i take into account the plate?


and even without the plate, when i first drop the meat from height 1m above the scale, the spring will still compress more than when it reaches equilibrium (mg=kx). so how do i find this initial compression ?

thanks
 
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  • #2
Using conservation of energy,

The loss in Potential energy of the meat and plate as the spring compress = gain in elastic potential energy of the spring.
 
  • #3
quietrain said:
so we can't use F=kx = mg here because the mg is for the piece of meat only, but how do i take into account the plate?
In the case of two objects (meat and plate) that impact and don't bounce apart, you can use conservation of energy and also the conservation of momentum to determine the velocity of the pair immediately after impact. Once they impact and move together with a new initial velocity, you can then apply conservation of energy to the pair of objects and compare it to the spring energy.
 
  • #4
A good engineering rule of thumb is that a dynamic strain is twice the static strain of the same load. Your load will be even higher than that since you are not only applying the strain dynamically, but with some initial kinetic energy.
 
  • #5
ok, so my equation is now mgh + 1/2mv^2 = 1/2 kx^2

but my m in mgh is the meat only? and h is the height above the plate?

my m in KE is meat + plate? v is final speed determined from conservation of momentum?

and so my x is the initial compression due to the impact?
 
  • #6
the mgh in ur context is wrong. You are double counting the loss in PE since you already took into account the Kinetic energy arised from the loss in PE
 
  • #7
oh. so my equation should be just 1/2mv^2 = 1/2kx^2 ?

where m is the total mass ??
 
  • #8
Looks right to me.
And v is the speed just after the meat lands (1/3 of the meat speed).
 
  • #9
ah ok thanks everyone
 

1. How does the weight of the meat affect the reading on the weighing scale?

The weight of the meat directly affects the reading on the weighing scale. The more meat you place on the scale, the higher the number on the scale will be.

2. Will the type of meat make a difference in the weight on the scale?

Yes, the type of meat will make a difference in the weight on the scale. Different types of meat have different densities and moisture levels, which can affect their weight.

3. Does it matter if the meat is raw or cooked when weighing it on a scale?

Yes, it does matter if the meat is raw or cooked when weighing it on a scale. Cooking can cause the meat to lose moisture, which can affect its weight. It's best to weigh meat when it is in its raw state.

4. How can I ensure an accurate reading when weighing meat on a scale?

To ensure an accurate reading, make sure the scale is calibrated correctly and that the meat is evenly distributed on the scale. It's also important to make sure the scale is on a flat, stable surface.

5. Can weighing meat on a scale help with portion control?

Yes, weighing meat on a scale can be a helpful tool for portion control. By accurately measuring the weight of the meat, you can ensure that you are consuming the recommended serving size and not overeating. This can be beneficial for managing calorie intake and maintaining a healthy diet.

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