Lift Upward Motion & Apparent Weight — NTSE in 59 Sec ⚡

 

❓ Question

Why does a person feel heavier when a lift accelerates upward?

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🖼️ Concept Image

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✍️ Short Solution

This is a pure Newton’s Second Law + apparent weight concept.
No calculation needed — just force direction clarity + equation setup 🔥

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🔹 Step 1 — Actual vs Apparent Weight (MOST IMPORTANT 💯)

Actual weight:

$$\text{Actual Weight} = mg$$

👉 Yeh constant hota hai (Earth ki gravity par depend karta hai)

Apparent weight:

$$\text{Apparent Weight} = N$$

👉 Jo tum feel karte ho = Normal Reaction

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🔹 Step 2 — Normal Reaction = What You Feel

👉 Lift ke floor ka jo force tum par lagta hai, wahi:

$$N = \text{Apparent Weight}$$

📌 Weighing machine bhi N measure karti hai, mg nahi

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🔹 Step 3 — Lift Moving Upward

👉 Jab lift upar accelerate karti hai, system ko upward accelerate karne ke liye extra force chahiye hota hai.

👉 Isliye floor tumhe extra push deta hai.

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🔹 Step 4 — Apply Newton’s Second Law

Net force:

$$F = ma$$

Upward direction positive:

$$N - mg = ma$$
$$N = m(g + a)$$

👉 Clearly:

$$N > mg$$

📌 Isliye tumhe heavy feel hota hai ✅

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🔹 Step 5 — NTSE Golden Traps

❌ Direct $N = mg$ likh dena
❌ Direction ignore kar dena
❌ Acceleration ka effect bhool jaana

⚠️ Golden Rule:

Lift upar → weight badhta hai

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✅ Final Answer

$$\boxed{\text{Apparent Weight increases (}N = m(g+a)\text{)}}$$

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⭐ Golden NTSE Insight

• Apparent weight = Normal Reaction (N)
• Lift upward:

$$N = m(g + a)$$

• Lift downward:

$$N = m(g - a)$$

🧠 One-line memory:

Lift upar → heavy feel | Lift neeche → light feel