Basic Concept Physics Question

[Loppyfoot]

Homework Statement

An object is moving in the +z direction. Which, if any, of the following statements do you know must be false? Check all that apply.

1. velocity of z is zero.
2. The net force on the object is in the -z direction.
3. The net force on the object is zero.
4. The net force on the object is in the +z direction.

Homework Equations

The Attempt at a Solution

check please:

Well the velocity of z cannot be zero, so that must be false.
the net force on the object is in the -z direction is not correct as well.
the net force on the object is not zero.
the net force on the object IS in the z direction.

are these answers correct?

 

[p21bass]

According to the way the question is worded - namely what do you know must be false - we only know that the velocity cannot be zero in the z-direction. As the question doesn't mention any acceleration, what do we know about any forces?