From what height should you drop a ball if you want it to hit the ground in exactly 3 seconds?
1 answer:
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Answer:
c.
Explanation:
- In absence of friction, total mechanical energy must be conserved.
- This means that the change in gravitational potential energy (in magnitude) must be equal to the change in kinetic energy:
- As it can be seen, the mass m is on the both sides of the equation, which means that it can be simplified.
- We can solve this equation for v (speed at the bottom) as follows:
- As it can be seen, the mass has no part in the equation, so, due both are starting from the same height, both people have the same speed at the bottom.
- The option c is the right one.