Question

1. a cart is set up as shown below, with three fans directed to the left and two of the fans running. the motion of the cart is represented by the v vs t graph shown. if the experiment were repeated with all three fans running, what might the resulting v vs t graph look like?

Explanation:

Step1: Understand the force - motion relationship

When more fans are running (from 2 to 3 fans running to the left), the net force to the left on the cart increases. According to Newton's second law $F = ma$, an increase in the net - force results in an increase in acceleration.

Step2: Analyze the v - t graph characteristics

The slope of a velocity - time ($v$ vs $t$) graph represents acceleration. In the original situation with 2 fans running, the cart has a certain positive acceleration (since the velocity is increasing with time). When all 3 fans run, the acceleration to the left increases. This means the slope of the $v$ vs $t$ graph will be steeper. Also, since the fans are pushing to the left, the velocity will increase in the negative direction (assuming left is the negative direction).

Step3: Evaluate the options

Option A shows a steeper negative - slope line, which indicates a larger acceleration in the negative direction. Option B shows a constant zero velocity, which is incorrect as there is a non - zero net force acting on the cart.

Answer:

A