Question

Newton’s 2nd Law experiment using an inclined plane Purpose This lab experiment is to verify Newton’s second law and in the process also obtain the coefficient of kinetic friction between a block and an incline. Theory Newton’s 2nd law states that the net external force on an object in a given direction is equal to the mass of the object multiplied by its acceleration, Fnet = ma, where m is the mass of the object and a is its acceleration. Applying Newton’s 2nd law to the two objects as shown in the figure below, we obtain: m1g – T = m1a (1) T – m2gSin – fk = m2a (2) where fk = kFn (3) and Fn = m2gCos (4) from (2),(3), and (4) T = m2a + m2gSin + km2gCos (5) From (5), and for  = 0, T = m2a + km2g (6) Following equation (5), a graph of T vs. a should give a straight line where the slope will be equal to m2, and the coefficient of kinetic friction may be obtained from the intercept, since the intercept will be equal to (m2gSin + km2gCos) Procedure Open the simulation at https://ophysics.com/f3.html a. Choose a constant value for mass m2. b. Choose a value for  c. Choose a coefficient of friction low enough for the masses to move, and keep this coefficient constant. Verifying the acceleration d. Choose a value for m1 e. Using the “run” and “pause” buttons, run and pause make a table of at least seven data sets of h (take the absolute value) and time. f. Make a graph of h vs. time, and an appropriate curve fit to obtain the acceleration from your graph. (Hint: x = vit + ½ at2) g. Compare the acceleration from your graph with that provided by the simulation. Verifying Newton’s 2nd Law h. Vary m1, and record the corresponding acceleration, a, and tension, T, for several (at least seven) values of m1. i. Create a table for T vs. a j. Make a graph of T vs. a k. Choose an appropriate curve fit to obtain m2 and k from your graph (Hint: Equation 5) l. Compare the m2 and k from your graph to the actual m2 and k m. Repeat steps g to k using  = 0 (Hint: equation 6) n. Compare the two k values obtained from j and k. (do a percent difference) Questions 1. If a constant nonzero force is applied to an object, what can you say about the velocity and acceleration of the object? 2. Why can we neglect forces such as those holding a body together when we apply Newton’s second law of motion? Sources: 1. CCSU Physics Lab Manual 2. Ophysics.com 3. OpenStax College Physics

Answer 1