A 2.0 kg mass is released from rest at the top of a plane at 20 degrees above the horizontal. The coefficient of kinetic friction between the mass and the plane is 0.20. What will be the speed of the mass after sliding 4.0 m along the plane?

Respuesta :

Answer:

3.97 m/s

Explanation:

given,

mass of the object,m= 2 Kg

angle of inclination,θ = 20°

coefficient of friction,μ= 0.2

distance,L = 4 m

using work energy theorem

[tex]W = \dfrac{1}{2}mv^2[/tex]..........(1)

now,

v   is the speed of the box.

W  is the work done on the box by a net external force.

Work done on the force

[tex]W = F_{net}L[/tex]

[tex]F_{net} = m g sin \theta - \mu N[/tex]

[tex]F_{net} = m g sin \theta - \mu (mg cos \theta)[/tex]

[tex]W = (mg sin\theta - \mu mg cos \theta)L[/tex]......(2)

now, equating both equation 1 and 2

[tex]\dfrac{1}{2}mv^2 = (mg sin\theta - \mu mg cos \theta)L[/tex]

 [tex]v= \sqrt{2 (g sin\theta - \mu g cos \theta)L}[/tex]

 [tex]v= \sqrt{2(9.8\times sin 20^0 - 0.15\times 9.8 \times cos 20^0)4}[/tex]

     v = 3.97 m/s

hence, the final speed of the box is equal to v = 3.97 m/s

Lanuel

The final speed the mass after sliding 4.0 meters along the plane is 3.48 m/s.

Given the following data:

  • Mass = 2.0 kg.
  • Angle = 20°
  • Coefficient of kinetic friction = 0.20.
  • Distance = 4.0 m.

Scientific data:

  • Acceleration due to gravity = 9.8 [tex]m/s^2[/tex]

To calculate the final speed the mass after sliding 4.0 meters along the plane, we would apply the work-energy theorem:

How to calculate the work done.

Mathematically, the work done on the block of ice is given by this formula:

[tex]Work =Fd[/tex]   .....equation 1.

But, [tex]F = mgsin \theta - \mu mgcos \theta[/tex]

So, the work done becomes;

[tex]W = (mgsin \theta - \mu mgcos \theta)d[/tex]   ....equation 2.

From the work-energy theorem, the work done is given by this formula:

[tex]W =\frac{1}{2} mv^2[/tex]   ....equation 3.

Equating eqn. 3 and eqn. 2, we have:

[tex]\frac{1}{2} mv^2 = (mgsin \theta - \mu mgcos \theta)d\\\\V=\sqrt{2(gsin \theta - \mu gcos \theta)d} \\\\V=\sqrt{2(9.8 \times sin 20- 0.20 \times 9.8 \times cos 20)\times 4.0}\\\\V=\sqrt{2(3.3518- 1.8418)\times 4.0}\\\\V=\sqrt{2(1.51)\times 4.0}\\\\V=\sqrt{12.08}[/tex]

V = 3.48 m/s.

Read more on work here: https://brainly.com/question/22599382