consider this situation: a child pulls a sled by a rope across the lawn at a constant speed. of the forces…

Explanation:

Step1: Analyze each force

• Normal Force: The lawn exerts an upward normal force on the sled to balance gravity.
• Gravity: Earth pulls the sled downward with gravitational force.
• Applied Force: The child's pull (tension in the rope) is an applied force, but tension is the force in the rope, and the applied force here is via tension. Wait, actually, the tension in the rope is the force pulling the sled (applied force via tension). Also, since it's moving at constant speed, net force is zero, so friction opposes the motion. Air resistance: when moving across the lawn, air resistance is present (though maybe small, but in physics, for motion, air resistance is a force). Wait, let's re - evaluate:
  • Normal: Present (lawn pushes up on sled).
  • Gravity: Present (Earth's pull).
  • Applied: The tension in the rope is the applied force (the child pulling is the source, so tension is the force acting on the sled, but also, the applied force is via tension. Wait, the options have tension and applied. Wait, no: the rope has tension, so tension is the force acting on the sled (pulling it). Then, friction: since it's moving at constant speed, friction must be present to balance the horizontal force (tension's horizontal component). Air resistance: when an object moves through air, air resistance acts opposite to motion. So:
  • Normal: Yes (from the lawn, upward).
  • Gravity: Yes (downward).
  • Tension: Yes (from the rope, pulling the sled).
  • Friction: Yes (opposing the motion, since speed is constant, so tension's horizontal component is balanced by friction).
  • Air Resistance: Yes (opposing the motion of the sled through air).
  • Applied: Wait, the applied force is the tension here? Wait, the child applies a force via the rope, so the force on the sled is tension (the force in the rope). So maybe the "Applied" here is a misnomer, but according to the options, let's check standard force analysis for a sled pulled at constant speed:
    • Forces on sled: Gravity (down), Normal (up, balances gravity), Tension (from rope, at an angle), Friction (opposing motion, horizontal), Air Resistance (opposing motion, horizontal). Since it's moving at constant speed, the horizontal components of tension, friction, and air resistance balance, and vertical components (gravity and normal) balance.

So the forces present are Normal, Gravity, Tension, Friction, Air Resistance. Wait, but let's check the options again. The options are Normal, Gravity, Applied, Friction, Tension, Air Resistance.

Wait, maybe the "Applied" force is considered as the tension (since the child applies the force via the rope, so tension is the applied force). But in physics, tension is the force in the rope, so the force on the sled is tension. So to correct:

• Normal: Present (balances gravity).
• Gravity: Present (downward).
• Tension: Present (pulling the sled).
• Friction: Present (opposing motion, since constant speed, so net force zero, so friction = horizontal component of tension).
• Air Resistance: Present (opposing motion through air).

Now, let's confirm each:

1. Normal Force: The sled is in contact with the lawn, so the lawn exerts an upward normal force. So present.
2. Gravity: All objects near Earth experience gravity. So present.
3. Tension: The rope is pulling the sled, so tension force acts on the sled. Present.
4. Friction: Since the sled is moving across the lawn, there is kinetic friction opposing the motion. Since it's moving at constant speed, friction must be equal in magnitude to the horizontal component of tension. Present.
5. Air Resistance: As the sled moves through the air, air resistance acts opposite to the direction of motion. Present.

What about "Applied"? The applied force is the force that an external agent (the child) applies. The child applies the force via the rope, so the force on the sled is tension (the force in the rope). So "Applied" as a separate force is not correct here, the force is tension. So the forces present are Normal, Gravity, Tension, Friction, Air Resistance.

Step2: Select the correct forces from the options

From the given options, the forces acting on the sled are Normal, Gravity, Tension, Friction, and Air Resistance. Also, wait, maybe the "Applied" force is considered as the tension - but in the options, we have to select the ones that are present. Let's go back to basic force diagrams for an object pulled at constant speed on a surface:

• Vertical forces: Gravity (down) and Normal (up) - balanced.
• Horizontal forces: Tension (pulling), Friction (opposing), and Air Resistance (opposing) - since constant speed, the sum of horizontal forces is zero (Tension's horizontal component = Friction + Air Resistance).

So the forces present are Normal, Gravity, Tension, Friction, Air Resistance.

Answer:

The forces acting on the sled are Normal, Gravity, Tension, Friction, and Air Resistance. So the selected forces should be: Normal, Gravity, Tension, Friction, Air Resistance. If we have to list the options:

• Normal (selected)
• Gravity (selected)
• Tension (selected)
• Friction (selected)
• Air Resistance (selected)

(Note: The "Applied" force is the tension here, so we select tension instead of applied as the force on the sled is tension from the rope.)