A 10 kg box is pulled across the floor at a constant velocity of 3.0 m/s. If the box is pulled with a force of 40 N, what is the size of the frictional force between the box and the floor?
Well, well, well, it looks like we have a case of "The Box and the Frictional Force"! So, my dear friend, when a box is pulled at a constant velocity, we are dealing with a special party animal called "equilibrium." In this case, the force of friction between our funky box and the floor must be equal in magnitude but opposite in direction to the pulling force. So, the size, or magnitude, of the frictional force is also 40 N. It's like a delightful game of tug-of-war, but without all the sweating and shouting!
To find the size of the frictional force between the box and the floor, we first need to understand the concept of net force. When an object is moving at a constant velocity, the net force acting on it is zero. In this case, since the box is pulled at a constant velocity, the net force on the box is zero.
The force applied to the box, in this case, is the force of the person pulling it, which is 40 N. Since the box is moving at a constant velocity, we can assume that the force of gravity is balanced by the normal force exerted by the floor.
The frictional force between the box and the floor opposes the motion of the box. Therefore, the frictional force must have the same magnitude as the force applied to the box in order to balance it, but in the opposite direction.
So, the size of the frictional force between the box and the floor is also 40 N.
To find the size of the frictional force between the box and the floor, we need to use Newton's second law of motion, which states that the net force acting on an object is equal to the product of its mass and acceleration.
In this case, since the box is moving at a constant velocity, there is no acceleration. Therefore, the net force acting on the box is zero. The force pulling the box, called the applied force, is equal in magnitude but opposite in direction to the frictional force. This means that the frictional force is 40 N in the opposite direction.
Therefore, the size of the frictional force between the box and the floor is 40 N.