A skydiver jumps out of a plane and reaches her terminal speed of 120 mph after falling for 15 s. How fast will the skydiver be going 5 s later at the moment she pulls the ripcord? (The parachute hasn't deployed yet)
terminal speed is terminal speed (ignoring change in air density as you drop)
To answer this question, we can use the concept of constant acceleration.
Terminal speed is the maximum speed an object can reach while falling due to the balance between the upward force of air resistance and the downward force of gravity. Once terminal speed is reached, the object's velocity remains constant.
Given that the skydiver reaches her terminal speed of 120 mph after falling for 15 seconds, we know her velocity is constant at 120 mph.
To find out how fast the skydiver will be going 5 seconds later, we need to determine if any additional forces are acting on her during this time. Since the parachute hasn't deployed yet, we can assume that the additional air resistance from the parachute can be neglected.
Since the skydiver's velocity is constant, there is no acceleration acting on her. Therefore, her velocity will remain the same even after 5 seconds.
Therefore, the skydiver will still be going at a speed of 120 mph at the moment she pulls the ripcord, given that there are no other forces acting upon her.