Michelle and George are studying the forces and motion of a 0.8-kg low friction cart on a horizontal table. They use a spring sc
ale to exert different amounts of horizontal pulling force on the cart and measure the acceleration of the cart for each pulling force. The measurements of each set of pulling force and acceleration are displayed in the table below. If friction is much weaker than the pulling force, which of the following is the best fit for the missing pulling force in the table?
Table 1: The horizontal pulling forces (F) and resulting acceleration (a) for the cart.
The cart experiences no motion when there is 0.1 N of horizontal force, so F=0 in this case. When one uses Newton's Second Law to find the acceleration caused by each force, it becomes clear that every row in the chart represents a horizontal force of approximately F=20 N. The best fit for the missing value is F=-30N.
