Gooluk, the Inuit, is pulling a 62kg sled through the snow on his way home from ice fishing. On the back of the sled is his 50kg sack of fishing tackle. The coefficient of sliding friction between the sled and the snow is .07 and the coefficient of sliding friction between the sled and the sack is 0.100. While pulling, the fishing rod sticking out of his sack catches on a tree branch, but Gooluk doesn't notice and keeps walking. What force does Gooluk need to exert to keep the sled moving with a constant speed while the sack pulled back across it?

Question

Gooluk, the Inuit, is pulling a 62kg sled through the snow on his way home from ice fishing. On the back of the sled is his 50kg sack of fishing tackle. The coefficient of sliding friction between the sled and the snow is .07 and the coefficient of sliding friction between the sled and the sack is 0.100. While pulling, the fishing rod sticking out of his sack catches on a tree branch, but Gooluk doesn't notice and keeps walking. What force does Gooluk need to exert to keep the sled moving with a constant speed while the sack pulled back across it?

Answer 1

I will be glad to critique your thinking.

Answer 2

To determine the force Gooluk needs to exert to keep the sled moving with constant speed while the sack is pulled back across it, we need to consider the different forces acting on the sled.

First, let's analyze the forces acting on the sled and the sack separately:

1. Forces acting on the sled:
- Weight of the sled: F_sled = mass_sled * g
- Normal force exerted by the ground on the sled: N_sled = mass_sled * g
- Sliding friction between the sled and the snow: F_friction_snow = coefficient_snow * N_sled

2. Forces acting on the sack:
- Weight of the sack: F_sack = mass_sack * g
- Normal force exerted by the sled on the sack: N_sack = mass_sack * g
- Sliding friction between the sack and the sled: F_friction_sack = coefficient_sack * N_sack

Since the sled is moving at a constant speed, the applied force by Gooluk must equal the sum of the forces opposing its motion.

Considering the forces above, the total force opposing the motion of the sled can be expressed as:

F_opposing = F_friction_snow + F_friction_sack

Substituting the formulas for each friction force and simplifying:

F_opposing = coefficient_snow * N_sled + coefficient_sack * N_sack
F_opposing = coefficient_snow * (mass_sled * g) + coefficient_sack * (mass_sack * g)
F_opposing = coefficient_snow * (mass_sled * g) + coefficient_sack * (mass_sack * g)

Next, we can substitute the given values in the equation and calculate the answer:

mass_sled = 62 kg
mass_sack = 50 kg
coefficient_snow = 0.07
coefficient_sack = 0.100
g = acceleration due to gravity, approximately 9.8 m/s²

F_opposing = 0.07 * (62 kg * 9.8 m/s²) + 0.10 * (50 kg * 9.8 m/s²)
F_opposing = 42.532 N + 49 N
F_opposing = 91.532 N

Therefore, Gooluk needs to exert a force of approximately 91.532 Newtons to keep the sled moving with a constant speed while the sack is pulled back across it.

I will be glad to critique your thinking.

thank you

To determine the force Gooluk needs to exert to keep the sled moving with constant speed while the sack is pulled back across it, we need to consider the different forces acting on the sled.