I will use these problems in class. You will probably ask for them, so here they are:

1. How hard (with how much force) would you have to push directly on a book to hold it against a wall?

Draw a free-body-diagram for this box.
screenshot_08
Assume the box has a mass of 1.3 kg, and the coefficient of static friction is 0.2





2. A model rocket has a mass of 250 grams and the engine provides a thrust of 7 Newtons for 4 seconds. Draw a free-body-diagram for the rocket while it is moving up with the engine on (ignore air resistance). If the rocket is fired straight up and starts from rest, what is the speed after 4 seconds? (you can assume the mass of the rocket does not significantly change)


3. For the rocket above, how high will the rocket be after the engine runs for 4 seconds?