Calculating the Force of a Falling Object | Momentum, Energy, Force Problem

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Rabbit food in the form of pellets is poured onto a scale pan at the rate of 400 pellets per second. Each pellet has a mass of 20 g and falls a distance of 2.0 m. Assuming that the pellets do not bounce, calculate the scale reading at 7.0 s.

[sebisomal]

Think you are wrong when you divide by 7 secs
The total force = weight accumulated a fraction of time before 7 deconds plus the impact force of pallets that made contact at 7th second.
For simplicity assume pallets fall together when clock hits a whole number, force will be weight after 6 seconds and then add impact at 7th second.
But calculating impact at 7th second is extremely tricky.

[mayukhpramanik]

helped me a lot sir i am really thankful

[supreethrkoundinya]

Thanks a lot. This video solved a lot of doubts!

[randerson]

I believe that the method used and the answer given are wrong. The time over which the pellets are dropped has nothing to do with the force of impact. If the pellets were dropped over 14 seconds (instead of 7 seconds) would the impact force at 14 seconds be half as much? Obviously not. In order to calculate the force of impact you need to divide the change in momentum at impact by the time it takes for the momentum to change AT IMPACT (i.e., for the velocity to go from 6.26 m/s to 0 m/s once striking the scale). The time for this negative acceleration to occur depends on the "give" of the scale -- for which the problem does not contain enough information to calculate. Also, wouldn't the force of impact be due to the mass of each pellet striking the scale, not the total mass of the pellets? What would the force of impact at seven seconds have to do with pellets dropped in the first second? (Assuming pellets dropped at an even rate over the seven seconds.) Minor point: only one sig-fig as mass is given as 20 g not 20. g

[ernestodiaz]

This description is incorrect. The change in momentum is equal to the force ma. W = change in potential energy and W = F*d. Therefore impact force is equal to F = mgh/d, where d represents the bounce after impact.

[msc.str.engineermohammedad]

how can I calculate the impact force of falling objects ?

[arielmcdowny]

My friend asked me the same question "if he falls from a tall building (20m) how many force did he generate after landing on to the ground"
And I'm stunned by that question because after all the physics problem that I solved and many formulas all I can think is F=ma. Wtf. 🤣

[ericstevens]

I got hit by a 50 lb hatch that fell 15 ft is it possible to calculate the force on impact

[TheCatIsAMonster]

Trying to figure out what would actually happen if super man’s key was 500, 000 tons and he accidentally dropped it from around 3 ft high

[kareemsalessi]

Falling pellets produce incorrect results. For the purpose of such calculations, afalling object must be a one piece solid object, such as a one kilo dumbell dropped on a scale.😮