consider this situation: a student attaches a rope to his book bag and drags the bag across the floor at a…

Explanation:

Step1: Analyze Gravity

Gravity acts on all objects with mass near Earth's surface, so the bag has gravity ($F_g$) pulling it down.

Step2: Analyze Normal Force

The floor exerts a normal force ($F_N$) upward on the bag to balance gravity (since vertical acceleration is zero).

Step3: Analyze Applied Force (Tension)

The rope exerts a tension (applied force via tension) on the bag to pull it horizontally.

Step4: Analyze Friction

Since the bag moves across the floor, kinetic friction ($F_f$) opposes the motion, acting opposite to the tension.

Step5: Analyze Air Resistance

At constant speed on a floor, air resistance is negligible or not a primary force here, but the main forces are Gravity, Normal, Tension (Applied), and Friction. Wait, the "Applied" here is via tension, but let's re - check: the rope provides tension (a type of applied force). So the forces present are Normal (from floor), Gravity (Earth's pull), Applied (tension from rope), Friction (from floor), and Tension (same as applied here? Wait, no: tension is the force in the rope, applied force is the force from the rope on the bag. So the forces acting on the bag are:

• Gravity: acts downward.
• Normal: acts upward (from floor, balances gravity).
• Tension: acts horizontally (from the rope, applied force).
• Friction: acts horizontally opposite to tension (kinetic friction, since it's moving at constant speed, so net force is zero, tension = friction).

Air resistance: for a book bag dragged at constant speed on a floor, air resistance is usually much smaller than friction and can be ignored in this context, but the main forces are Normal, Gravity, Tension (Applied), and Friction. Wait, the options are Normal, Gravity, Applied, Friction, Tension, Air Resistance. Let's correct: the rope's force on the bag is tension (so Tension is present), which is the applied force. So the forces acting on the bag are:

1. Gravity: Always acts on objects with mass near Earth.
2. Normal: The floor pushes up on the bag, balancing gravity.
3. Tension: The rope pulls the bag (this is the applied force here, so Tension is present, and "Applied" could be considered as tension, but the option is "Tension" and "Applied"? Wait, maybe the "Applied" is the tension force. Anyway, the forces present are Normal, Gravity, Tension (from rope), Friction (from floor), and since the bag is moving at constant speed, the horizontal forces (tension and friction) are equal, vertical forces (gravity and normal) are equal. Air resistance is negligible here.

So the forces that act on the bag are Normal, Gravity, Tension, Friction, and the applied force is tension, so "Applied" might be a misnomer, but among the options, the correct ones are Normal, Gravity, Tension, Friction. Wait, let's go step by step:

• Gravity: Yes, because the bag has mass, so $F_g = mg$ downward.
• Normal: Yes, the floor exerts an upward normal force to balance gravity (since $a_y = 0$), so $F_N = F_g$.
• Tension: Yes, the rope exerts a tension force on the bag to pull it horizontally.
• Friction: Yes, since the bag is moving across the floor, kinetic friction opposes the motion, so $F_f=\mu_k F_N$, and since $a_x = 0$ (constant speed), $F_{tension}=F_f$.
• Applied: The "Applied" force here is the tension force, so Tension is the applied force from the rope. So Tension is present, and Friction is present, Gravity and Normal are present. Air Resistance: For a book bag dragged at constant speed on a floor, air resistance is very small and not a significant force here, so we can ignore it.

Answer:

The forces acting on the bag are Normal, Gravity, Tension, and Friction. So the selected options should be Normal, Gravity, Tension, Friction (and Applied is Tension here, but the option "Tension" is more accurate for the rope's force on the bag). So among the given options, the forces present are: Normal, Gravity, Tension, Friction. (If we consider "Applied" as the tension, then Applied (Tension) is also present. So the correct selections are Normal, Gravity, Tension, Friction, and Applied (since Tension is the applied force from the rope). Wait, maybe the "Applied" is a general term for the force from the rope, so Tension is the specific type of applied force. So to sum up, the forces acting on the bag are:

• Normal (from the floor, upward)
• Gravity (from Earth, downward)
• Tension (from the rope, horizontal)
• Friction (from the floor, horizontal opposite to tension)

Air Resistance: Negligible for this situation.