Last name: First name: Date: Period: Newton s 2 nd Law of Motion Notes (pg. 1) Notes (pg. 2) Problems (pg. 3) Lab Pt. 1 Lab Pt. 2 5 4 3 2 1 LATE 1. What does Newton s 2 nd Law state? (pg. 148) The of an object depends on the of the object and the amount of applied. 2. What is the formula that represents the 2 nd Law? (pg. 149) 3. Using the above formula, what are the TWO KEY POINTS OF THE LAW? (pg. 148) Key Point #1 More force acceleration Key Point #2 More mass acceleration (for the same amount of force) 4. Golf ball and Ping pong ball DEMO Prediction (Which will hit the ground first?) Observation 5. Explain your actual observation above. Gravity accelerates the two objects at rates. 1
6. Calculate the acceleration due to gravity of an apple and watermelon. (pg. 149) APPLE WATERMELON 7. If the apple and watermelon have the same acceleration when dropped, why don t they hit the ground at the same time? (pp. 139-140) slows down acceleration. Air resistance is a type of. The amount of air resistance depends on the and of the object. Example: Feather vs Apple 2
Example Problems: What is the force required to accelerate a 5000 kg helicopter at a rate of 3 m/s 2? A boy pushes a grocery cart forward with a total mass of 30 kg. What is the acceleration of the cart if the net force on the cart is 60N? More challenge: An object is accelerating towards the Earth at 10 m/s 2. If the force on the object due to gravity is 70N, what is the mass of the object? 3
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Newton s 2 nd Law Part 1 CONSTANT FORCE, CHANGING MASS DIRECTIONS: Set up a blue car with a 1 ounce fishing weight pulling it down. You will pull the car with 100 grams in it (.1 kg) and with 500 grams (.5 kg) and compare the acceleration of your 2 cars. Allow the force of the fishing weight to pull it the distance of the counter. INFORMAL OBSERVATIONS ABOUT THE CAR S ACCELERATION Car with.1 kg of mass (light car) Car with.5 kg of mass (heavy car) The light car took MORE / LESS time to reach the end of the counter than the heavy car. This meant that it went FASTER / SLOWER and had MORE / LESS acceleration. The heavy car took MORE / LESS time to reach the end of the counter than the light car. This meant that it went FASTER / SLOWER and had MORE / LESS acceleration. FORMAL CALCULATIONS: Calculate the acceleration of the 2 cars using Newton s. NOTE: FORCE needs to be measured in NEWTONS and MASS in KILOGRAMS Calculate the Acceleration of the LIGHT CAR Calculate the Acceleration of the HEAVY CAR SUMMARY (answer in complete sentences): IF YOU INCREASE THE MASS OF AN OBJECT, WHAT HAPPENS TO ACCELERATION? Provide data from your experiment to support your answer. 5
Newton s 2 nd Law Part 2 CONSTANT MASS, CHANGING FORCE DIRECTIONS: This time you will ALWAYS KEEP 500 grams (.5 Kg) in your car. However, you will pull the car with 1 ounce of fishing weight on the first trial and with 2 ounces of weight on the 2 nd trial. INFORMAL OBSERVATIONS ABOUT THE CAR S ACCELERATION Car with pulled with only 1 oz Car pulled with 2 oz The car pulled with a lighter weight (less force) took MORE / LESS time to reach the end of the counter than the car pulled with a heavier weight (more force). This meant that it went FASTER / SLOWER and had MORE / LESS acceleration. The car pulled with a heavier weight (more force) took MORE / LESS time to reach the end of the counter than the car pulled with a lighter weight (less force). This meant that it went FASTER / SLOWER and had MORE / LESS acceleration. FORMAL CALCULATIONS: Calculate the acceleration of the 2 cars using Newton s. NOTE: FORCE needs to be measured in NEWTONS and MASS in KILOGRAMS Calculate the Acceleration of the car pulled with 1 OZ weight Calculate the Acceleration of the car pulled with 2 OZ weight SUMMARY (answer in complete sentences): IF YOU INCREASE THE FORCE PUSHING OR PULLING AN OBJECT, WHAT HAPPENS TO ACCELERATION? Provide data from your experiment to support your answer. 6