Power and speed: P = Fv
"Power and speed: P = Fv" is a free, interactive Class 11 Physics simulation for NEET and JEE, built on the NCERT section "Power" in Work, Energy and Power. A car with a constant-power engine: F = P/v falls as v rises; against drag or a slope it reaches a top speed where P = Fv balances losses. NEET has asked about this idea 3 times in 10 years of papers. JEE Main asked 44 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
From the lesson Power in Work, Energy and Power. Change the values and watch what happens.
What it shows
NCERT § Power
A car with a constant-power engine: F = P/v falls as v rises; against drag or a slope it reaches a top speed where P = Fv balances losses.
Controls
4 to try
- Toggleconstant force / constant power
- Sliderengine power 10–100 kW
- Sliderroad slope 0–10°
- Slidercar mass 800–2000 kg
Try this
Choose the power so a 1000 kg car climbs a 5° slope at a steady 20 m/s (≈17 kW ignoring drag).
Common mistake
Thinking power fixes the force rather than F·v.
In NEET
10 years of papers
Asked 3 times in 10 years of NEET.
See the past questions: Work-Energy Theorem, Work, Energy and Power (chapter)
In JEE Main
42 shifts analysed
44 questions from Work, Energy and Power across the 42 JEE Main shifts Lumi has analysed (2017–2026).
The idea behind it
NCERT § "Power"
- Power is the rate of doing work. Average power = W/t; instantaneous power P = dW/dt.
- Instantaneous power can also be written P = F·v, the dot product of force and velocity.
- The SI unit of power is the watt, 1 W = 1 J s⁻¹. One horsepower is 746 W.
- The kilowatt hour is a unit of energy, not power: 1 kWh = 3.6 × 10⁶ J.
- A pump lifting mass m of water through height h in time t does useful work at the rate mgh/t; if its efficiency is η, the input power is (mgh/t)/η.
- Efficiency is useful output power divided by input power and is always less than 1 for real machines.
Questions
5 answers
- What does the "Power and speed: P = Fv" simulation show?
- A car with a constant-power engine: F = P/v falls as v rises; against drag or a slope it reaches a top speed where P = Fv balances losses.
- What mistake does the "Power and speed: P = Fv" simulation fix?
- A common mistake it clears up: thinking power fixes the force rather than F·v.
- Has NEET asked about this idea?
- Yes. NEET has asked about this idea 3 times in 10 years of papers.
- Does JEE Main ask questions from Work, Energy and Power?
- Yes. JEE Main asked 44 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
- Is this simulation free?
- Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Power" in Work, Energy and Power (Class 11 Physics).
Embed this simulation
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