What is the weight in newtons of a 30-kg suitcase?
What is the weight in pounds?

A 400-kg sailboat accelerates at a rate of 1.5 m/s2. What is the net force acting on it?

HINT: On which planet? ;)

Pounds is a tricky unit, because it can be a unit of both weight and mass.

All of these questions can easily be answered using F = ma, and some conversion factors.

Let me know if you need any more help.