What is the restoring force of a spring with a spring constant of 4a and a stretched displacement of 3b? a. –7 ab b. `-7 a/b ` c. –12 ab d. `-12 a/b`

Gordon is going for a run through the park, but it is cold outside. the low outside temperature could affect his personal safety.

What is the kinetic energy of a baseball moving at a speed of 40 m/s if the baseball has mass of 0.15 kg?

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.