this: 1. Without any weight inside, pull the box along the floor. Try to do this with a constant force. Take note on how much force you are using to pull the box car. IN 2. Add an additional mass to the box and pull the cart towards you. Do you notice and change in the amount of force you are applying to move the box? 3. Keep adding more mass and take note of the tension in the string you are pulling and in the force you are applying. Add more weight until the box becomes difficult to pull. 4. Is there a difference in the force needed to get the box to move with more weight added? Explain. __

1. **Initial Pull (No Weight):** When you first pull the empty box, you'll experience a small amount of resistance due to friction between the box and the floor. The force you apply will be relatively small and, ideally, constant. Try to maintain a steady pull rather than jerking the box. Record this initial force (it might be helpful to use a spring scale attached to the string to measure this directly).<br /><br />2. **Adding Mass:** As you add mass to the box, you'll notice that you need to apply *more* force to pull the box with the same constant speed. This is because the increased mass increases the inertia of the box. Inertia is the resistance of an object to changes in its motion. A heavier object has more inertia and therefore requires a larger force to overcome that inertia and start it moving (or to change its speed).<br /><br />3. **Increasing Mass:** With each addition of mass, the force required to pull the box will increase. You'll feel the increased tension in the string as you pull. As the box gets heavier and heavier, it will become increasingly difficult to maintain a constant speed. This demonstrates the direct relationship between mass, force, and acceleration (or in this case, maintaining constant speed against friction).<br /><br />4. **Difference in Force:** Yes, there is a significant difference in the force needed to move the box as more weight is added. This is explained by Newton's Second Law of Motion, which states that force equals mass times acceleration (F=ma). In your experiment, you're not necessarily *accelerating* the box continuously, but you *are* overcoming the force of friction to keep it moving at a constant speed. The force of friction also increases with the weight (mass) of the box. Therefore, a greater force is required to overcome the increased friction and maintain the motion of the heavier box. The more mass you add, the greater the force required to pull the box.<br />