Net Force Questions: Calculating Frictional Force

[jessical_x3]

Homework Statement

A student drags an object across a laboratory table at constant velocity using an applied force of 12 Newtons. Calculate the frictional force

2. a horizontal force of 15 Newtons pulls a 5 kg block along a horizontal surface. If the force produces an acceleration of 2 m/s(squared), what is the frictional force acting on the block?


(add FBD)

 

[jumbogala]

You need to show some of your own work, an attempt at the solution, before anyone will help you.

 

[thomate1]

The frictional force is the force that opposes the motion of an object when it is in contact with a surface. To calculate the frictional force, we need to consider the applied force and the mass of the object.

For the first question, the frictional force can be calculated using the formula Ff = μN, where μ is the coefficient of friction and N is the normal force. Since the object is moving at a constant velocity, the net force on it is zero. This means that the applied force of 12 Newtons is equal and opposite to the frictional force. Therefore, the frictional force is also 12 Newtons.

For the second question, we can use Newton's second law, F = ma, to calculate the frictional force. The applied force of 15 Newtons is equal to the sum of the frictional force and the force required to accelerate the object. Therefore, the frictional force can be calculated as 15 - (5 kg * 2 m/s^2) = 5 Newtons.

In both cases, the frictional force is equal to the applied force due to the object moving at a constant velocity or the sum of the applied force and the force required to accelerate the object.