(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

An adult is pulling two small children in a sleigh over level snow. The sleigh and children have a total mass of 47kg. The sleigh rope makes an angle of 23degrees with the horizontal. The coefficient of kinetic friction between the sleigh and the snow is 0.11. Calculate the magnitude of the tension in the rope needed to keep the sleigh moving at a constant velocity.

2. Relevant equations

Fk=μFn

Fg= mg

ƩFx=ma(x)

ƩFy=ma(y)

3. The attempt at a solution

Fn≠Fg

Fn= Fgcosθ

= mgcosθ

= (47kg)(9.8m/s^2)cos23

Fn= 424N

Fg=mg

=(47kg)(9.8m/s^2)

Fg=461N

Fk=μFn

= (0.11)(424N)

Fk=46.64N

If it is to move at a constant velocity, there would be no acceleration

ƩFx=ma(x)

Ft+ (-Fk)=ma(x)

Ft=ma(x)+Fk

but if there is no acceleration then a=0

Ft=Fk

But, that's not the case.

Ideas?

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# Tension and friction on an angle

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