The mass of a lift is $2000 ext{ kg}$. When the tension in the supporting cable is $28000 ext{ N}$, then i

Question

The mass of a lift is $2000 	ext{ kg}$. When the tension in the supporting cable is $28000 	ext{ N}$, then its acceleration is: (Take $g=10 	ext{ m/s}^2$)

Accepted Answer

1. **Identify Forces:** The forces acting on the lift are the tension $T$ (acting upwards) and the weight $mg$ (acting downwards).
2. **Compare Forces:** 
   - Upward force $T = 28000 	ext{ N}$.
   - Downward force $W = mg = 2000 	imes 10 = 20000 	ext{ N}$.
   - Since $T > mg$, the net force is directed upwards, meaning the lift accelerates upwards.
3. **Apply Newton's Second Law:** The net force $F_{net}$ equals mass times acceleration ($ma$).
   $$ F_{net} = T - mg = ma $$
4. **Calculation:**
   $$ 28000 - 20000 = 2000 	imes a $$
   $$ 8000 = 2000 	imes a $$
   $$ a = \frac{8000}{2000} = 4 	ext{ m/s}^2 $$
   (Reference: NCERT Class 11, Physics Part I, Chapter 5: Laws of Motion, Section 5.5).

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