A research team uses a force sensor to measure the horizontal friction force on a…
PHYSICS · Multi-part · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
A research team uses a force sensor to measure the horizontal friction force on a variety of masses pulled at constant speed across the same metal surface. The team plots the six data points on a graph of measured friction force Fpull (vertical axis, N) versus normal force Fn (horizontal axis, N). A linear least-squares fit to the data yields a best-fit line with slope 0.27 and vertical intercept 0.05N. Uncertainties in both slope and intercept are reported as ±0.02 in their respective units.
(a) Identify the physical quantity represented by the slope of the best-fit line and state its expected ideal value in this experiment.
(b) Using the best-fit parameters, determine a value (with units) for the quantity identified in part (a) and quote the associated uncertainty.
(c) Discuss two plausible experimental reasons why the vertical intercept is not exactly zero, even though theoretical models predict it should be.
(d) Propose one specific change to the experimental procedure that could reduce the absolute value of the intercept in a future data set. Justify your suggestion based on frictional physics and data-collection principles.