- #1
Boogeyman
- 76
- 0
Homework Statement
Sand is poured at a steady rate of 5g/s onto the pan of a direct reading balance calibrated in grams. If the sand falls from a height of 0.20m onto the pan and it does not bounce off the pan then, neglecting any motion of the pan, calculate the reading on the balance 10s after than sand first hits the pan.
The Attempt at a Solution
I thought the solution was to simply find the mass of sand that would fall after 10s i.e 50g. However this is not the answer.
Evidently, the height from which it falls must therefore affect the reading on the balance. Does the acceleration that occurs in the fall affect the reading? If this is the case, I am tempted to find Potential Energy.
PE=mgh
PE=(0.05)(10)(0.2)
PE=0.1J
Since energy is conserved then the total energy remains the same:
PE of sand before being poured=KE of sand before it hits the pan
KE=0.1J
KE=1/2 mv2
Now if any of this was correct, how do I find v?