Ncert Exercises & Solutions

Q. 22 A truck is pulling a car out of a ditch by means of a steel cable that is 9.1 m long and has a radius of 5 mm. When the car just begins to move, the tension in the cable is 800 N. How much has the cable stretched?

(Young's modulus for steel is $2 \times 10^{11} N / m^{2}$ )

Hint: Use the concept of Young's modulus.

Step 1:Find the change in length of the cable.

Length of steel cable, l = 9.1 m

Radius, r = 5mm =

5 \times 10^{- 3} m

Tension in the cable, F = 800 N

Young's modulus for steel, Y =

2 \times 10^{11} N / m^{2}

Change is length,

∆ l = ?

Young's modulus, (Y)

= \frac{F}{A} \times \frac{l}{∆ l} \Rightarrow ∆ l = \frac{F}{{πr}^{2}} \times \frac{l}{Y}

= \frac{800}{3.14 \times {(5 \times 10^{- 3})}^{2}} \times \frac{9.1}{2 \times 10^{11}}

= 4.64 \times 10^{- 4} m

NEET Information

courses

Company

Botany Questions

Chemistry Questions

Physics Questions

Zoology Questions