HW Solutions # 8 - 8.01 MIT - Prof. Kowalski Momentum and Collisions.
1) 8.55
Please review section 8.6 rocket Propulsion in the book. a) The average thrust is impulse devided by time: Fave = J t (1)
So the ration of the average thrust to maximum thrust i
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Physics Department
8.044 Statistical Physics I
Spring Term 2003
Practice Exam #2
Problem 1 (25 points) Elastic Rod
For a certain elastic rod of length L, tension F , and temperature T the following
facts are known.
i)
879: Following the suggestions in the book, one can rst show that
the angle between the two outgoing pucks is 90°. Momentum conservation
yields two equations:
mar/1,3 = rrthJ cos a + mow cos (1)
D = m'uAj sin a: + m'ubdr sin ,6 (2)
If we square and add th
Problem 1 (30 points)
In lecture, you saw a demo with a parallel plate capacitor with
capacitance C0. The capacitor was connected to an ideal power
supply with an output voltage V and charged to a charge Q.
The capacitor was disconnected from the power su
\ § i th 1L
- L_r_~J
x d3 x
T gem u-m/éo
it Lt-
E.lf\= (TA/é.
w
E = E}
*q AA 1 Lt- :3 E30
W H in:
- Q 6
5:2. YE- 1-) C O
H o
\[qL : '\ L 86 \Q-JE a! .:
Réa
Q 7' C : -
A
0% A a 1 A
c, *3 Ch/L
0 A Q
V 4y}_hq1
73 P 3 1V 7.
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HW Solutions # 7 - 8.01 MIT - Prof. Kowalski
Potential Energy Curves, Momentum and Center of Mass.
1) 7.61
We use conservation of energy Ki + Ui + Wother = Ei + Wother = Ef = Kf + Uf (1)
12 12 mv1 + mgy1 + Wother = mv2 + mgy2 (2) 2 2 I will measure the gr
Problem 1 Solution:
(a)
N
T
F
F friction
T
T
m2
m2 g
m1
m1 g
(b) The block m1 moves in x-direction:
m1 a = F cos T N ,
N = m1 g F sin
The block m2 moves in y-direction:
m 2 a = T m2 g
Put in the values of m1 , m2 , F , and , we obtain
1
12M g
4
)
3M a =4
Problem 1 (25 points)
Shown below is a circuit consisting of a power supply with an
output voltage V and three identical light bulbs. For all
answers, explain your reasoning in one or two sentences.
(a) Which of the bulbs will burn most brightly or will t