# Homework Help: Need answer to homework problem please

1. Nov 27, 2005

### drod

a book falls off a bookshelf and hits the floor. given this info calculate the force of the book on the floor.
mass of the book 1.5kg the book touched the floor for .3 sec. the velocity of the book the moment the book hit the floor 3m/s.
the velocity of the book when it bounced off the floor 1m/s.

2. Nov 27, 2005

### NEWO

you need to calculate the accelration of the book when it hits the floor, ie if the book falls at 3m/s and is incontact with the floor for 0.3s then the acceleration is?????(you work that one out) then use newtons 2nd law of motion

and bobs your uncle

I think that is right

newo

3. Nov 27, 2005

### Fermat

You are dealing with an impulse question here. The eqn to use is,

Ft = Δp

F is the force providing the impulse,
t is the (small) duration of the impulse
Δp is the change in momentum

4. Nov 27, 2005

### NEWO

ahhhh yes i miss read the question sorry guys
:yuck:

5. Nov 27, 2005

### Fermat

No prob - feel free to help

Your solution would have worked, but, in essence it would simply condense down to using the impulse formula I posted.

6. Nov 27, 2005

### NEWO

sorry bit out of context but what part of the north east you from
im at loughborough university in my final year in physics

i hope to do a phd

7. Nov 27, 2005

### Fermat

I'm from Scotland originally, living in Newcastle. I've been to university 4 times, got two degress, one (ordinary) in Computer Science and one (Hons, 1st) in Maths. I started my Masters a while ago but gave up. I may go back to it soonish, via the OU.

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