Monday

December 22, 2014

December 22, 2014

Posted by **amy** on Tuesday, March 27, 2012 at 2:54pm.

- physics -
**Ness**, Tuesday, March 27, 2012 at 3:45pmok, im not good at physics but i'll give it a try. this may be a silly question but the ground they are on is snow right?

- physics -
**amy**, Tuesday, March 27, 2012 at 10:53pmyes i guess it would be snow

- physics -
**Elena**, Wednesday, March 28, 2012 at 2:11pmThe equation of motion is (in vector form)

vector (m•g) + vector F(fr)+ vector N+vectorF =0

Projections on the axes

x: F•cosα-F(fr) = 0

y: -mg+N+F•sinα = 0

F(fr) = F•cosα,

N =mg- F•sinα,

F(fr) = k•N =k•(mg- F•sinα),

F•cosα= k•(mg- F•sinα),

k = F•cosα/(mg- F•sinα) =

= 45•0.866/(50•9.8-45•0.5) = 0.083.

W= W(F) + W(fr)=F•cosα•s +F(fr) •s=

= F•cosα•s +k•N•s =

= s• (F•cosα + k•(mg - F•sinα)) =

=500 (45•0.866 + 0.083•(50•9.8 - 45•0.5)=38885 J

**Answer this Question**

**Related Questions**

physics - A boy exerts a horizontal force of 2nt to pull his 2kg sled over the ...

Physics - A boy pulls a sled with a force of 40 N on a rope 2.5 meters long. The...

physics - an adult exerts a force of 26n to pull a child across the snow on a ...

Pre-calculus - Nathaniel pulls a sled along level ground with a force of 30 ...

physics - a man pulls an 80 kg sled up an incline that is at an angle of 25 ...

Physics - The sled is stuck in the snow. A child pulls on the rope and finds ...

Physics - A boy pulls a sled with a force of 40N on a rope 2.5 meters long. The ...

Physics - A jack exerts a vertical force of 4.5 x 10^ 3 newtons to raise a car 0...

Physics - A sled which has a mass of 45kg is sitting on a horizontal surface. A ...

physics - Jack is driving with a pail of water along a straight pathway at a ...