Question

An iron sphere of 1kg is moving a velocity of 20m/s on a cemented floor. It comes to rest after
travelling a distance of 50m. Find the force of friction between the sphere and the floor.
( F = -4N)

Answer 1

Explanation:

an iron sphere of 1kg is moving a velocoty of 20 m s-1on a cemented floor It comes to rest after travelling a distance of 50m Find the force of friction ...

Answer 2

$\displaystyle\large\underline{\sf\red{Given}}$

✭ Mass of the sphere (m) = 2 kg

✭ Initial Velocity (u) = 20 m/s

✭ Final Velocity (v) = 0 m/s

✭ Distance (s) = 50 m

$\displaystyle\large\underline{\sf\blue{To \ Find}}$

◈ The Force of friction between the sphere & the floor?

$\displaystyle\large\underline{\sf\gray{Solution}}$

So here we may find the acceleration with the help of,

$\displaystyle\sf \underline{\boxed{\sf v^2=2as+u^2}}$

And then the frictional force will be given by,

$\displaystyle\sf \underline{\boxed{\sf F = ma}}$

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$\underline{\bigstar\:\textsf{According to the given Question :}}$

Finding the acceleration of the sphere,

➝ $\displaystyle\sf v^2-u^2=2as$

➝ $\displaystyle\sf 0^2-20^2 = 2\times a \times 50$

➝ $\displaystyle\sf -400=100a$

➝ $\displaystyle\sf \dfrac{-400}{100} = a$

➝ $\displaystyle\sf \orange{Acceleration = -4 \ m/s^2}$

Now the frictional force will be,

➳ $\displaystyle\sf F = ma$

➳ $\displaystyle\sf F = 1\times (4)$

➳ $\displaystyle\sf \pink{Force_{Friction} = -4 \ N}$

$\displaystyle\sf \underline{\sf\therefore Frictional \ Force \ is -4N}$

Note : Here the force is negative meaning that the force is applied in the opposite direction of the motion

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$\displaystyle\sf \underline{\bullet\:\textsf{Know \ More}}$

»» $\displaystyle\sf v = u+at$

»» $\displaystyle\sf s = ut+\dfrac{1}{2}at^2$

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