Blog 6: Skydiving

My sister turned 18 this month and after seeing pictures of my brother skydiving in florida, she decided she wanted to go, too. My parents paid for it as her birthday present :)

Skydiving is a perfect exapmle to show air resistance, however air resistance is just one of the forces relevant to a bigger concept we're studying, impulse and momentum. Starting when my sister jumped out of the plane she started gaining speed increasing her momentum (p=mv) until she hit terminal velocity and momentum and acceleration remained constant. The impulse (J) she hit the ground with was also affected by air resistance.

J=Fxt

Air resistance and the parachute increased the time it took my sister to fall and decreased the force she hit the ground, therefore the overall impulse was smaller opposed to jumping with no parachute.

Work those stairs!

Here we are at the bottom of weinberg staircase, and we don't look to happy to go to class because our lockers are on the third floor. Have you ever wondered if going up the other stairs is less work? (sorry i dont have a picture of the other stairs, but we all know they have a steeper incline). After the lab stimulation when we pulled the cart up various inclines of ramps, I realized both stairs require the same work. Since work is the change in total energy and only potential energy has changed we can use W=mgh to find work done. Although going up the stairs shown in the picture you have to travel a longer distance, in both scenarious you reach the same height so the work done is equal. Why does it seem harder to go up the other stairs then? Because the other stairs have a higher incline it requires more force to get up them while the stairs in the picture have a smaller incline requiring less force. To calculate work done using this information you would use
W=Fcos(theta)(displacement) where the shorter distance compensates for the larger force once again making the work done in both scenarios the same.