Mead. 2. Now suppose Ralph pushes on a 10 kg wagon filled with some dirt, causing it to accelerate at 5 m/s. Ignoring friction and assuming Ralph pushes with the same force, what is the acceleration of the wagon if we change the amount of dirt and therefore the mass to: a) 20 kg? b) 30 kg? 1 c) 50 kg? d) 100 kg? e) 5 kg? f) 2 kg? 3. Ralph pushes on a wagon and accelerates it at 6 m/s. What is the new acceleration of the wagon if: a) Ralph pushes with twice as much force and the mass of the wagon is doubled? b) Ralph pushes with three times as much force and the mass of the wagon is tripled? c) Ralph pushes with three times as much force and the mass of the wagon is doubled? d) Ralph pushes with twice as much force and the mass of the wagon is tripled? 4. Mass is sometimes described as the "difficulty of acceleration" of an object. How does Newton's Second Law agree with this description? Net Force, Mass, and Acceleration Newton's Second Law can be summarized in the equation net force acceleration = mass nel a= m When the net force is measured in units of Newtons (N) and the mass is measured in kilograms then the acceleration will be in units of m/s. The following diagrams demonstrate Newton's Second Law. Each box has a mass of 5 kg and is being pushed by one or more people. We are assuming the boxes are in free space and there is no friction. 25 N 15 N 10 N 10N 10 N 20 N net force = 10 N to the right acceleration = 10 N/5 kg 2 m/s to the right = net force = 15 N to the left acceleration = 15 N/5 kg = 3 m/s to the left = net force = 5 N to the right acceleration = 5 N/5 kg = 1 m/s to the right 5. Determine the magnitude and reaction of the net force acting on the following bor determine the magnitude and decon of the acceleration of the bones Assume the boxes free space and there is no friction a) mass of box-2kg magmade of net force direction of net force magnitude of acceleration= direction of acceleration tant velocity. 5. Determine the magnitude and direction of the net force acting on the following boxes. Then determine the magnitude and direction of the acceleration of the boxes. Assume the boxes are in free space and there is no friction. a) mass of box = 2 kg 22 N magnitude of net force 15 N direction of net force = magnitude of acceleration = direction of acceleration = b) mass of box = 8 kg 18 N magnitude of net force = direction of net force = magnitude of acceleration = direction of acceleration = 14 N c) mass of box = 3 kg magnitude of net force = 4N direction of net force magnitude of acceleration = direction of acceleration = 10 N 6 N d) mass of box = 0.5 kg 44N magnitude of net force = = to direction of net force = 9 N magnitude of acceleration = 3 N direction of acceleration = 4 N e) mass of box = 7 kg magnitude of net force = direction of net force = 3 N 2 N magnitude of acceleration = 5N direction of acceleration = 30 N to Iph Which of the boxes in question 5 could be at rest and remaining at rest? Explain your answer. 7. Which of the boxes in question 5 could be moving with constant velocity? Why or why not? 8. Could the box in question 5a be moving to the left? If so, is its speed increasing, decreasing, or constant? If not, explain why not. 9. Could the box in question 5a be moving to the right? If so, is its speed increasing, decreasing, or constant? If not, explain why not. 10. Suppose the box in question 5a is moving down. How does the net force affect its motion? Problem Solving 11. The diagram below shows a person with a mass of 70 kg hanging from a rope. There are two forces acting on the person, indicated by the arrows. a) What is the magnitude of the net force on the person? b) What is the magnitude of the acceleration of the person? The rope pulls up on the person with 735 N of force The Earth exerts a 700 N gravitational force down on the person c) What is the direction of the person's acceleration? d) Can we tell which direction the person is moving? Why or why not? 12. The graph below shows the velocity vs. time The mass of the ear is 1000 kg. Answer the graph of a car traveling on a straight section of road. s that follow based on this graph