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A 2 kg mass starts from rest on an inclined smooth surface with inclination 30^{o} and length 2 m. How much will it travel (in meters) before coming to rest on a surface with coefficient of friction 0.25?

 

Option: 1

4


Option: 2

6


Option: 3

8


Option: 4

2


Answers (1)

best_answer

As we learned

 On the horizontal road

  A block of mass m is moving initially with velocity u on a rough surface and due to friction, it comes to rest after covering a distance S.

  •            Distance traveled before coming to rest (S):

F=ma = \mu R

ma = \mu mg

a = \mu g

V^{2}=u^{2}-2as

S = \frac{u^{2}}{2\mu g}=\frac{P^{2}}{2\mu m^{2}g}

a = acceleration 

\mu= coefficient of friction

S = distance traveled

g = gravity

u=initial velocity

V = finally velocity

P=initial mometum=mu

 

 

 

On the inclined road :

 

a=g[sin\theta+\mu cos\theta]

V^{2}=u^{2}-2aS

0=u^{2}-2g[sin\theta+\mu cos \theta]S

S=\frac{u^{2}}{2g(sin\theta+\mu cos\theta)}

S= distance traveled

\mu= coefficient of friction

V = Final velocity

u = Initial velocity

By using this concept, 

 

So First on incline plane 

v^{2}=u^{2}+2as=0+2\times g\; \sin 30\times 2

Let it travel distance 'S' before coming to rest on a horizontal surface

S=\frac{v^{2}}{2\mu g}=\frac{20}{2\times 0.25\times 10}

                    

                     = 4m

Posted by

Gaurav

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