Question

consider this situation: a child pulls a sled by a rope across the lawn at a constant speed. of the forces listed, identify which act upon the sled. tap to select the forces that are present. normal gravity applied friction tension air resistance

Explanation:

• Normal force: The ground exerts a normal force on the sled perpendicular to the surface of the lawn. This force counteracts the vertical component of the sled's weight (due to gravity) and any vertical component of the tension in the rope.
• Gravity: The Earth's gravitational pull acts on the sled, pulling it downward towards the center of the Earth. The magnitude of this force is \(F_g = mg\), where \(m\) is the mass of the sled and \(g\) is the acceleration due to gravity (\(g = 9.8\ m/s^2\)).
• Applied force (tension): The child is pulling the sled with a rope. The force exerted by the rope on the sled is a tension force. This is an applied force that has both horizontal and possibly vertical components (depending on the angle at which the child is pulling).
• Friction: Since the sled is moving across the lawn, there is kinetic friction between the sled and the grass. Kinetic friction opposes the relative motion between the sled and the surface. The force of kinetic friction is given by \(F_f=\mu_k N\), where \(\mu_k\) is the coefficient of kinetic friction and \(N\) is the normal force.
• Air resistance: As the sled moves through the air, air molecules exert a resistive force on the sled. This force opposes the motion of the sled. The magnitude of air - resistance force \(F_{air}\) generally depends on the speed of the sled (\(F_{air}\propto v^n\), where \(n\) is usually between 1 and 2 for low - to - moderate speeds) and the cross - sectional area of the sled.

Answer:

Normal, Gravity, Applied (Tension), Friction, Air Resistance