Physics1lab3NewtonsLaws

 To add mass, I taped washers to the straw. Experiment 1 – inertia – Newton’s first law of motion. See page 119 of Physics by James Walker, 5 th edition, for a statement of Newton’s First Law of Motion. Student : Abstract In experiment 1, we are focusing on Newton’s first law of motion that states every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by an external force acting upon it. This is the law of inertia and we will be showing how this law works using a container filled with water. We test the law by moving the container with various forces and motions. This will show how inertia works and why the object at rest or in constant motion will stay that way unless it has a net force acting on it. Water Bowl 1. Fill the container with a couple of inches of water. 2. Find an open space outside to walk around in with the container of water in your hands. 3. Perform the following activities and record your observations of each motion in Table 1: a. Start with the water at rest (e.g., on top of a table). Grab the container and quickly accelerate it. JWH 3 Physics I

You will use the metal washers to make the masses. You can tie the washers to the string or use a hanger, such as a paper clip. If you do use a hanger you will have to include its mass into the total mass, mass of washers + mass of hanger. You will use 15 washers to make the larger mass and 5 washers to make the smaller mass. Use enough string to allow a mass to fall to floor when starting from near the pulley. The other mass is going from the floor to near the pulley. With the masses hanging from the pulley, the greater mass near the top, measure the distance the mass will fall to the floor. Time the fall of that mass. Calculate the acceleration of the falling mass: y = ½ a t 2 : we assume no initial velocity when you started timing, that is you just let it drop and started timing when you let go. From the above we solve for a (acceleration): a = 2 y t 2 Note: This assumes you do not have a constant velocity. A constant velocity could occur with a significant pulley friction. Having masses with a large difference in value helps reduce the effect of pulley friction. Record 10 trials. Data table for the Atwood Machine experiment (Experiment 2, Procedure 1): Height = _1.8_ meters Mass of 10 washers = _20_ grams Mass of 5 washers = _10_ grams M 1 = _10_ grams (lighter mass) M 2 = _20_ grams (heavier mass) Trial Number Fall time (sec) Calculated acceleration (m/s 2 ) 1 .72 sec 2(1.18) / .72= 3.28 m/s 2 2 .70 sec 3.37 m/s 2 3 .68 sec 3.47 m/s 2 4 .75 sec 3.15 m/s 2 5 .73 sec 3.23 m/s 2 6 .64 sec 3.69 m/s 2 7 .68 sec 3.47 m/s 2 8 .72 sec 3.28 m/s 2 JWH 6 Physics I

Stopping suddenly with the water diagram: acceleration is in the backward direction, same as the stopping force. What is the direction of the water’s acceleration. The water’s acceleration is in the same direction as the force that acts upon it. Describe two instances where you feel inertial forces in a car. 1. Inertia forces can be felt in a car when the car brakes suddenly. The sudden movement will originally pull your body forward with the car and until the car stops, we are still moving. This is your body’s inertia resisting the movement of the car backwards as it brakes. 2. You can oppositely feel the same inertia forces when you suddenly accelerate in a car. Your body is at rest when the car is at rest and then sudden acceleration forward will push your body backwards. This is your body’s inertia resisting the force of being moved forward, JWH 9 Physics I

Conclusions Overall, this experiment was interesting to complete and kept me entertained. I found it really fascinating how we could demonstrate Newton’s laws of motion through real life scenarios. First, with the water resistance in experiment 1 showing the law of inertia. Second, the Atwood Machine Pulley in experiment 2 showed the application of the second law of motion. This showed a physical example of how acceleration, mass, and force are all linked. Thirdly, we used the balloon powered vehicle of experiment 3 in order to show Newton’s third law of motion and showed the scenario of every action having an equal and opposite reaction. I felt like I was able to gain a real understanding of the laws of motion from this experiment and found it engaging and exciting. JWH 12 Physics I