# Velocity & acceleration

Missing homework template due to originally being posted in other forum.
This is not a homework question so I have posted here.
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The question relates to velocity and acceleration. I think the answer of the book is incorrect.

Description: A coin is rolled along the balcony edge at the steady speed of 0.46 m/s before falling off the edge after 2.4 seconds. It then accelerates due to gravity and hits the ground after 8 seconds at a speed of 78.4 m/s. Assume that no air resistance acts on the coin.

The first part of the question asks how far the coin rolls before falling off the edge of the balcony. I got this part correct with the answer 1.1 m.

The second part asks: calculate the acceleration of the coin during its fall.

My calculation is:   The book just writes So the book seems to have forgotten that the initial velocity of the coin was 0.46 m/s. Have they just assumed that the coin started from 0 m/s velocity or am I missing something? Please advise. Thank you

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Seems to me the velocity was .46 horizontally then vertically it starts at 0.

Bandersnatch
or am I missing something?
Yes, you are. Remember that velocity is a vector.

velocity is a vector.

So that means the vertical velocity is 0m/s at onset (as jerromyjon said) and it is only the horizontal velocity that is 0.46 m/s ??

Bandersnatch
That's right.

Thanks all. This forum is great.

Don't let the "Thanks all" stop you ... keep posting if there's more to say

Bandersnatch
Well, if you care for a follow-up question to test your new understanding, perhaps you could try answering how far from the edge of the balcony the coin lands?

Well, if you care for a follow-up question to test your new understanding, perhaps you could try answering how far from the edge of the balcony the coin lands?

I think this is going to involve triangles, sine and cosine etc. That's beyond me at the moment. Maybe in a few months be able I'll look at this follow up question again

DEvens