In this video, we solve a problem involving work, energy, and power. We find how much work is done in lifting an injured trekker out of a sinkhole
📢 Access Solved Problems and PDFs: ▶ thesciencecube...
📢 Join our Telegram Channel: ▶t.me/TheScienc...
Problem Statement:
A mountain rescue team lifts an injured trekker directly upward and out of a sinkhole in three stages, each covering a vertical distance of 10.0 meters:
The trekker is accelerated to a speed of 5.00 m/s.
The trekker is lifted at a constant speed of 5.00 m/s.
The trekker is decelerated to zero speed.
We need to determine how much work is done on the 80.0 kg trekker by the lifting force during each stage.
Solution Breakdown:
Stage (a): Accelerating to 5 m/s
Work done by gravity (W₁):
W₁ = -mgd = -80.0 kg × 9.8 m/s² × 10.0 m = -7840 J
Work done by the lifting force (W₂):
Using the work-energy theorem: W₁ + W₂ = ΔK
-7840 J + W₂ = 1/2 × 80.0 kg × (5.00 m/s)²
W₂ = 8840 J
Stage (b): Lifting at a constant speed of 5 m/s
Work done (W) = mgd = 80.0 kg × 9.8 m/s² × 10.0 m = 7840 J
Stage (c): Decelerating to zero speed
Work done by gravity (W₁):
W₁ = -mgd = -80.0 kg × 9.8 m/s² × 10.0 m = -7840 J
Work done by the lifting force (W₂):
Using the work-energy theorem: W₁ + W₂ = ΔK
-7840 J + W₂ = 0 - 1/2 × 80.0 kg × (5.00 m/s)²
W₂ = 6840 J
Key Takeaways:
The work done by gravity is negative in each stage because it opposes the trekker's movement.
The work done to accelerate the trekker involves calculating the change in kinetic energy.
During constant speed, the work done equals the force of gravity multiplied by the distance.
The work done to decelerate the trekker is similar to the acceleration stage but involves reducing kinetic energy.
Understanding the work-energy theorem is crucial for solving such problems efficiently.
Make sure to like, comment, and subscribe for more physics problem-solving videos. If you have any questions or topics you’d like us to cover, drop them in the comments below!
Who is this for: Class 11 physics student, AP Physics 1, AP Physics C student, IGCSE Physics student or an IB Student
Негізгі бет Work Kinetic Energy Theorem Problem: 🏔️ Mountain Rescue Example
Пікірлер: 1