Question

a worker is pushing a wheelbarrow and is accelerating (speeding up) on a level, straight path. the two vertical forces in this event are gravity and a normal force. the vertical forces are balanced. the three horizontal forces are applied force, friction, and drag or resistance. the horizontal forces are unbalanced. the net force in this event is not zero and is in the direction of the motion not zero and is opposite to the direction of the motion zero

Explanation:

Step1: Analyze vertical forces

The wheel - barrow is on a level path. Gravity acts downwards and the normal force acts upwards. Since there is no vertical acceleration, the vertical forces are balanced.

Step2: Analyze horizontal forces

The wheel - barrow is accelerating (speeding up). According to Newton's second law ($F = ma$), for there to be acceleration, there must be an unbalanced force. The applied force is in the direction of motion and friction and drag are opposite to the direction of motion. Since it is accelerating, the net horizontal force is in the direction of motion.

Step3: Determine net force

As the wheel - barrow is accelerating, from $F = ma$ (where $a>0$), the net force $F_{net}$ is not zero and is in the direction of the motion.

Answer:

not zero and is in the direction of the motion