What is the meaning of the slope of the ΔEtot vs

What is the meaning of the slope of the ΔEtot vs

Subject: Physics    / General Physics    

Question
Post lab 4
——————————————————1. What is the meaning of the slope of the ΔEtot vs. time graph? Was that slope positive or negative? What
does that imply about your results? Briefly explain.
2. In our experiment, we ended up with PE and KE being polynomial order 2 in time on our graphs. Using
the assumption of constant acceleration (v=at , x=1/2at2) show that both PE and KE should be polynomial
order 2 in time.
3. In the calculation, we considered the rotational kinetic energy of the pulley, but why we did not consider
the potential energy of the pulley?
4. In terms of energy, why is it easier to go down a hill on a bike than it is to go up a hill? Why do we need
to keep peddling when we are on flat ground?
5. A roller coaster car is given a horizontal velocity of v=9.0m/s just before falling down a “valley” that is
d=300cm deep, as shown below. After the valley, the car encounters a hump with an unknown height.
Ignoring friction, what is the minimum height that the hump needs to have to prevent the car from getting
to the other side of it?

6. One object (A) is twice as heavy as another one (B). They fall off of a table at the same time. What is true
about the potential energy (PE) and the kinetic energy (KE) at the bottom (assuming that the bottom
represents a height of zero)? Briefly explain your answer.
a. PE of A < PE of B, KE of A > KE of B
b. PE of A > PE of B, KE of A > KE of B
c. PE of A > PE of B, KE of A = KE of B
d. PE of A = PE of B, KE of A = KE of B
e. PE of A = PE of B, KE of A > KE of B