Question

What is the direction of the frictional force? What is the direction of the normal force? How does the frictional force depend on the normal force? Let the x-axis be parallel to the incline and the y-axis rise from the incline at a right angle. By Newton's second law, if there is no acceleration in the y-direction (perpendicular to the plane), what must be the magnitude of the normal force? Use Newton's second law and the x-components of the forces to find the acceleration. m/s2

Answer 1

What is the direction of the frictional force?

Answer:

Direction of friction is always opposite to relative motion

Explanation:

Friction always resist the relative motion of two surface so it is always opposite to the direction of relative velocity

What is the direction of the normal force?

Answer:

It is perpendicular to the contact plane

Explanation:

Normal force is the perpendicular force which is always at 90 degree with the contact surface

How does the frictional force depend on the normal force?

Answer:

$F_f = \mu F_n$

Explanation:

Friction force is directly proportional to the normal force so we can say it is given as

$F_f = \mu F_n$

Let the x-axis be parallel to the incline and the y-axis rise from the incline at a right angle. By Newton's second law, if there is no acceleration in the y-direction (perpendicular to the plane), what must be the magnitude of the normal force?

Answer:

$F_n = mg cos\theta$

Explanation:

Normal force is equal to the component of the weight opposite to the direction of normal force

$F_n = mg cos\theta$

Use Newton's second law and the x-components of the forces to find the acceleration. m/s2

Answer:

$a = gsin\theta$

Explanation:

As we know that

$F_{net} = ma$

$mg sin\theta = ma$

$a = gsin\theta$