Respuesta :
Answer:
net work done by friction = - 2205 J
Explanation:
given,
mass of sled = 80 kg
slide down at an angle of 18°
length = 90 m
travel horizontally = 20 m before starting back up a 16° incline.
net work = ?
[tex]h_i = initial\ height[/tex]
[tex]h_i = L_i Sin 18^0[/tex]
[tex]h_i = 90 sin 18^0[/tex]
[tex]h_i = 27.81\ m[/tex]
[tex]h_f = Final\ height[/tex]
[tex]h_f = L_f Sin 16^0[/tex]
[tex]h_f = 90 sin 16^0[/tex]
[tex]h_f =24.81\ m[/tex]
net work done by friction = change in potential energy
= mg (h_f - h_i)
= (75) (9.8) (- 27.81 + 24.81)
net work done by friction = - 2205 J
Friction force s a type of opposition force acting on the surface of the body that tries to oppose the motion of the body. Net work done on the sled by friction will be -2250 J.
What is the friction force?
It is a type of opposition force acting on the surface of the body that tries to oppose the motion of the body. its unit is Newton.
Mathematically it is defined as the product of the coefficient of friction and normal reaction.
The given data in the problem is;
m is the mass of sled = 80 kg
Θ is the angle of slide down at an angle = 18°
l is the length = 90 m
W is the net work=?
On the inclined plane the trigonometry is applied then;
For initial height
[tex]\rm h_i=L_isin\theta \\\\ \rm h_i=90sin18^0 \\\\ \rm h_i=27.81 m[/tex]
For final height
[tex]\rm h_f= L_fsin\theta \\\\ \rm h_f= 90sin16^0 \\\\ \rm h_f=24.81 \ m[/tex]
Net work done by the friction = change in the potential energy
Net work done = [tex]\rm mg (h_f - h_i) = (75) (9.8) (- 27.81 + 24.81) = -2250\ J[/tex]
Hence the net work done on the sled by friction will be -2250 J.
To learn more about the friction force refer to the link;
https://brainly.com/question/1714663
