Answer:
D) Gravity and friction are acting on the person. The forces are balanced. There is no net force because the person is moving at a constant velocity
Step-by-step explanation:
Net Force
The first Newton's Law explains that a body keeps its velocity or at rest unless a net force is exerted on it. The second Newton's law gives us a mathematical expression for that net or unbalanced force as:
where m is the mass of the object and a its acceleration. Recall a body at constant velocity has zero acceleration.
The question describes how a person is sliding down a water slide at a constant velocity. That's all we need to know there is no net force acting on it. All the forces are balanced. The only possible options supporting this statement are B and D. We don't know if there is air resistance (B) or friction (D), but option B suggests the forces are balanced until the person reaches the bottom of the water slide. Option D is correct because the forces are balanced all the time