Calculating work in physics

In my physics class we are calculating work and the equations just keep messing me up, from what I read work = force times distance but then I just did the example problems, and checked my answers and they were totally wrong q.q one of the examples I did was

A tugboat pulls a ship with a consistent net horizontal force of 5.00 X 10^3 N and causes the ship to move through a harbor. How much work is done on the ship if it moves a distance of 3.00 km?

When I did this problem I just times them all together and I got 15,000 J
(The book says the answer is 1.50 x 10^7 J) if you know how to do this problem can you please explain (in detail) how you achieved it? =x

You forgot that all units must be compatible.
For SI we use Newtons, Joules and metres.
You MUST convert anything that does not fit this.
For example km
so 3.00 km -> 3.00 * 10 ^ 3 m ( 3000 m)
multiply 3.00 * 10 ^ 3 * 5.00 * 10 ^ 3
-> 15.0 * 10 ^ 6 J which is identical to 1.50 * 10 ^ 7 J ( or if not using standard form 15000000J fifteen million Joules, fifteen Mega Joules)

Your answer was incorrect because the unit for work should be in S. I. units, that is Joule = Newton x metre. But in the question, distance is given in km, so change it first to metre.
3 km = 3 x 10^3 m
Now, put the values,

W = F x d
W = 5 x 10^3 x 3 x 10^3 = 15 x 10^6, which is the same as 1.5 x 10^7.........................ANS

Hi there...

Basically as you said Work = Force x Distance

SI UNIT OF FORCE= Newtons(N)

SI UNIT OF DISTANCE= metres (m)

1KM = 1000m

Therefore DISTANCE = 3.00KM X 1000m = 3000m



Therefore WORK = FORCE X DISTANCE

.... WORK = 5.00 X 10^3 X 3000m = 1.50 x 10^7 J

your distance in 30km first change in metres
1km=1000metres
3km=3000
Now solve it
Work = Force*Distance=5.0*10^3 *3000 =15000*10^3 =1.5*10^4 *10^3
=1.50*10^7 your ans.

3.00 km is 3000 metres.