Which term refers to a variable that is not allowed to change during an experiment

Emmy kicks a soccer ball up at an angle of 45° over a level field. she watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. consider only the time that the ball is in the air, after being kicked but before landing. take "north" and "up" as the positive ‑ and ‑directions, respectively, and use ≈10 m/s2 for the downward acceleration due to gravity.

The photo shows sugar dissolved into a solution with excess sugar at the bottom of the jar this type of solution is classified as a. unsaturated b. compound c. saturated d. plasma

Aforce of 8,480 n is applied to a chart to accelerate it at a rate of 26.5 m/s2. what is the mass of the cart?