What pushes the crate forward?
"What pushes the crate forward?" is a free, interactive Class 11 Physics simulation for NEET and JEE, built on the NCERT section "Friction" in Laws of Motion. A crate on a truck bed: static friction points forward and accelerates the crate; beyond μs g it slips and kinetic friction acts. NEET has asked about this idea 2 times in 10 years of papers. JEE Main asked 39 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
From the lesson Friction in Laws of Motion. Change the values and watch what happens.
What it shows
NCERT § Friction
A crate on a truck bed: static friction points forward and accelerates the crate; beyond μs g it slips and kinetic friction acts.
Controls
4 to try
- Slidertruck acceleration 0–6 m/s²
- Sliderμs 0.1–0.8
- Sliderμk 0.05–0.6
- Slidercrate mass 10–100 kg
Try this
With μs = 0.4, find the largest truck acceleration before the crate slides (3.9 m/s²), and note the friction direction.
Common mistake
Friction always opposes the body's motion; friction always equals μN.
In NEET
10 years of papers
Asked 2 times in 10 years of NEET.
See the past questions: Friction Forces, Laws of Motion (chapter)
In JEE Main
42 shifts analysed
39 questions from Laws of Motion across the 42 JEE Main shifts Lumi has analysed (2017–2026).
The idea behind it
NCERT § "Friction"
- Friction is the part of the contact force that lies parallel to the surfaces; between the surfaces it opposes relative motion, or impending relative motion.
- Static friction is self-adjusting: it takes whatever value, up to a maximum, is needed to prevent sliding, f_s ≤ μ_s N.
- Its limiting value (f_s)max = μ_s N depends on the nature of the surfaces but not on the area of contact.
- If the applied force is less than the limiting value, static friction equals the applied force and the body stays at rest; it is not automatically μ_s N.
- Once sliding begins, kinetic friction acts: f_k = μ_k N, roughly independent of speed and area of contact. Usually μ_k < μ_s.
- Friction on a body can act along its direction of motion: the friction on a box on the floor of an accelerating truck points forward and is what accelerates the box.
- Rolling friction is much smaller than sliding friction, which is why wheels, ball bearings and lubricants are used to reduce energy loss.
- Friction is not purely a nuisance; walking, driving and braking all depend on it.
Questions
5 answers
- What does the "What pushes the crate forward?" simulation show?
- A crate on a truck bed: static friction points forward and accelerates the crate; beyond μs g it slips and kinetic friction acts.
- What mistake does the "What pushes the crate forward?" simulation fix?
- A common mistake it clears up: friction always opposes the body's motion; friction always equals μN.
- Has NEET asked about this idea?
- Yes. NEET has asked about this idea 2 times in 10 years of papers.
- Does JEE Main ask questions from Laws of Motion?
- Yes. JEE Main asked 39 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 "Friction" in Laws of Motion (Class 11 Physics).
Embed this simulation
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