Ancilla applies a force of 200 N [E] horizontally to pull a 38 kg sled across the snow at a constant velocity for 200 m.

(a) Draw a FBD of the sled

1 answer

To draw a Free Body Diagram (FBD) of the sled, we display the forces acting on it. Here's how the forces can be represented:

  1. Weight (\( W \)): The force due to gravity acting downward. It can be calculated as: \[ W = m \cdot g = 38 , \text{kg} \cdot 9.81 , \text{m/s}^2 \approx 373.8 , \text{N} , [\down] \]

  2. Normal Force (\( N \)): The force exerted by the surface upward. For a horizontal surface with constant velocity, the normal force will balance the weight of the sled: \[ N \approx 373.8 , \text{N} , [\up] \]

  3. Applied Force (\( F_a \)): The force applied by Ancilla to pull the sled, which is given as 200 N [E].

  4. Frictional Force (\( F_f \)): Since the sled is moving at a constant velocity, the frictional force will be equal in magnitude and opposite in direction to the applied force (acting to the west). Therefore, \( F_f = 200 , \text{N} , [W] \).

Summary of Forces in FBD

  • Upward Force: Normal Force \( N = 373.8 , \text{N} , [\up] \)
  • Downward Force: Weight \( W = 373.8 , \text{N} , [\down] \)
  • Rightward Force (East): Applied Force \( F_a = 200 , \text{N} , [E] \)
  • Leftward Force (West): Frictional Force \( F_f = 200 , \text{N} , [W] \)

In your FBD:

  • Draw a box to represent the sled.
  • Draw an arrow pointing down labeled as \( W \) (373.8 N) for the weight.
  • Draw an arrow pointing up labeled as \( N \) (373.8 N) for the normal force.
  • Draw an arrow pointing right labeled as \( F_a \) (200 N) for the applied force.
  • Draw an arrow pointing left labeled as \( F_f \) (200 N) for the frictional force.

This will illustrate that the sled is in equilibrium, with all forces balanced.