A 55.0 kg box is placed on an inclined plane that makes an angle of 28.0 degrees with the horizontal. The coefficient of static friction between the box and the inclined plane is 0.680. Determine the static frictional force which holds the box in place.

Respuesta :

Answer:

253 N

Explanation:

The forces acting on the box in the direction along the ramp are two:

- The component of the weight in the direction parallel to the ramp, [tex]mg sin \theta[/tex], acting down along the ramp

- The force of static friction, [tex]F_f[/tex], acting up along the ramp

The equation of motion along this direction is:

[tex]mg sin \theta - F_f= ma[/tex]

where:

m = 55.0 kg is the mass of the box

[tex]g=9.8 m/s^2[/tex] is the acceleration of gravity

[tex]\theta=28^{\circ}[/tex] is the angle at the base of the ramp

a is the acceleration of the box

However in this proble, the box is at rest, so the acceleration is zero:

[tex]a=0[/tex]

Therefore, the equation becomes:

[tex]mg sin \theta -F_f[/tex]

From which we find the static frictional force:

[tex]F_f=mg sin \theta = (55.0)(9.8)(sin 28.0^{\circ})=253 N[/tex]

The static frictional force which holds the box in place will be:

"253 N".

Static friction force

According to the question,

Mass of box, m = 55.0 kg

Acceleration due to gravity, g = 9.8 m/s²

Angle, θ = 28°

By using equation of motion,

→ mg Sinθ - [tex]F_f[/tex] = ma

When the box is at rest, the acceleration "a" be "zero (0)".

then,

→ mg Sinθ - [tex]F_f[/tex] = 0

hence,

The static frictional force be:

[tex]F_f[/tex] = mg Sinθ

By substituting the values,

     = 55.0 × 9.8 × Sin 28.0°

     = 253 N

Thus the above answer is correct.

Find out more information about friction here:

https://brainly.com/question/9204359