Final answer:
The work done by the rope on the sled is zero because the sled is moving at a constant speed, indicating that there is no net change in kinetic energy. Energy considerations in a physics context, like in this problem, usually involve calculations of work and energy, associated with forces such as gravity, friction, and applied forces.
Step-by-step explanation:
The question relates to the concept of work done in the context of physics, specifically using Newtons's second law of motion to calculate the work done by various forces on a sled being lowered down a hill. Here we consider a scenario where a rescue sled and victim with a total mass of 90.0 kg are being lowered down a 60.0° slope at constant speed. The forces involved include friction, the tension in the rope, the force of gravity, and we are asked to calculate the work done by each of these forces as well as the total work done over a distance of 30.0 m.
Calculations of work:
- The work done by friction can be calculated by using the formula: Work = force x distance x cos(θ), where θ is the angle between the force and the direction of motion.
- The work done by the rope is zero since it is maintaining the sled at a constant velocity, which implies no net work is done overall as there is no change in kinetic energy.
- The work done by the gravitational force is found by the product of the gravitational force component along the slope and the distance moved.
- The total work is the sum of all individual works done by each force acting on the sled.
To specifically address part (b) of the question, the work done by the rope is essentially the negative of the work done by friction because it is opposing the motion caused by gravity and friction to maintain constant speed. However, since speed is constant, kinetic energy doesn't change, and as work is defined as the change in kinetic energy, the work done by the rope in this context would be zero.