physics question

[mmmhelp]

Tom is chasing Jerry across the surface of a table 1.5m above the floor. At the last second Jerry steps out of the way and Tom slides off the edge at a speed of 5.0 m/s. Where will Tom strike the floor and what velocity components will he have just before he hits?

[jake-the-peg]

You need to use Newton's laws of motion.

First find out how long it takes Tom to hit the ground

Use X=Ut + �at�

In the vertical plane X is the height of the table and a is the acessleration due to gravity (9.8 m/s) U is 0 because that's the initial speed vertically.

Work out t (the number of seconds to impact)

Now you can think horizontally

Apply the same formula

Now X is the distance from the table tom will strike - there's no acceleration so it's just

X=Ut youre given U (5m/s) and you've just worked out t.

The horizontal velocity component is unchanged because there's no acceleration

The Vertical velocity component you can get from V=U+at
U is 0 of course and a is still the acceleration due to gravity.

Best of luck

[jake-the-peg]

Before I get picked up on it acceleration is m/s� not m/s

[Peter Pedant]

Long answer

how long will J take to hit the floor

h = 1/2 gt 2 h is 1.5 and g is 10

so t turns out to be root - three over ten

bleeach - they might have given numbers taht fit together well. Call this a half

J travels along at 5 m/s for half a second, which is around 2.5 metres out.

velocity components - Oh God that is why the answer is so long - see above - Vh is 5 as ever
and Vvert is gt which is 10 x half or 5 again

Trouble with me is that I start to answer the q
without reading the whole lot.

Good question

I have Fatty Barratt to thank for this analysis who taught me dynamics in 1968 - clearly very um clearly. He used to rattle through these.