Unformatted text preview: 2. A 0.03 kg mass of goop is launched upward at an angle from a frictionless spring launcher and surface (see picture at right). The goop eventually hits the ground, sticking in place. The spring has a spring constant of 14.0 N/rn, and the mass is initially pulled back a distance of 0.2 meters from the spring’s equilibrium position. \
The mass is initially 0.5 m above the ground. Set your y = 0 to be at the ground. ”‘020 m (a) Write an expression for the total energy of the system in terms of all the energy
systems that are changing from the time the mass is motionless on the spring to just
before it hits the ground. You must write subscripts on your energy terms indicating
a specific time in which you can calculate a value [no numbers here; you will calculate Eror in part (b)]. (b) Find a numerical value for ETOT in units of Joules. You must explain under which conditions and how you
determined this value. (c) (Extra credit: 10%) Find the speed of the gOOp (ﬁnal speed) just before it hits the ground. You must show
your work. Additional uestions 1) Plot the KB for the ﬂowerpot in problem 1. 2) Redo the plot of PE and KB for the ﬂowerpot if the F0 is now located at the ground. Did ETOT change? Why or why not? If, yes, then what is its value? 3) For problem 2: set y:0 at the height where the goop starts (i.e., 0.5 m above ground). What is Eror
now? 4) Find the ﬁnal speed of the goop just before it hits the ground for this new y=0, using the new value for
ETOT. Remember the yIO has changed; what is your PEg(ﬁnal) value in this case?. Write out the formula
for Eror in terms of all the E(ﬁnal) terms, and then solve for the speed. You should get the same value as before. Show your work. Quiz 5
10
1. All parts of this question refer to two elements, A and (r = atom separation in units of 10 m)
B, whose atomatom potentials are shown below. ;i‘ , ; 14.; , ﬂ ' [is ' ' ' ' ; (a) Are the molar volumes (volume of one mole) of these
two elements in the liquid phase the same, or is one greater than the other? Answer and clearly explain your reasoning below.
For parts (b) and (c): ﬁll in the blanks with a numerical reading from the appropriate axis (without units) for each
atom type. (b) What is the equilibrium separation of the two atoms
(for each atom type) when they are bound? potential energy in units of 10'21 J A: B:
(c) Consider the following situation for parts (i) — (ii): The total energy of each system of two atoms is —1.5.
(i) At what separation(s) is the speed of the particles zero?
A: B:
(ii) What is the maximum kinetic energy for each system? A: B: It must be clear to the grader how you got your answer to this part; show your work below. ...
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 Spring '08
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