Two girls pull a 15 kg sled, each with her own rope. They pull horizontally at an angle of 30 degrees from each other with identical forces of 27 N each. The coefficient of friction between the snow and the sled is 0.1. The acceleration of gravity is 9.8 m/s 2 . What is the acceleration of the sled?

Respuesta :

Answer:

The acceleration of the sled [tex]a= 2.468 \frac{m}{s^{2} }[/tex]

Explanation:

Using Newton's law the force the tow girls are making pulling the sled get an acceleration so:

[tex]F=m*a[/tex]

However the forces make the system in equilibrium and can find the force total os the system to find the acceleration of the system

∑F=F=0

[tex]m=15kg\\u=0.1\\F1=F2=27N\\[/tex]

∑F=Fj=0

The force F1 is in the same axis so the F2 have component in axis 'y' and F1 in axis 'y' is zero

[tex]N+F2*sin(\alpha)=m*g\\N+27N*sin(30)=15kg*9.8\frac{m}{s^{2} } \\N=15kg*9.8\frac{m}{s^{2} }-27N*sin(30)\\N=133.5N[/tex]

[tex]f=u*N\\f=0.1*133.5N\\f=13.35N[/tex]

The total force is in axis 'x' so:

[tex]Ft=F1+F2*cos(30)-f\\Ft=27N+27N*cos(30)-13.35N\\Ft=37.03[/tex]

[tex]Ft=m*a\\a=\frac{Ft}{m} \\a=\frac{37.03N}{15kg}\\a=2.468 \frac{m}{s^{2} }[/tex]

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