1) A force of 6N is applied at an angle of 60° to the horizontal. Another force of 8N is applied at an angle of 80° to the horizontal. 2) The total force is calculated as the square root of the sum of the squares of the individual forces. 3) Kinetic energy is calculated from the mass and velocity of an object. The kinetic energy is then used to calculate the temperature increase of the object.

1. 2/12/2007
Física
PADRÃO DE RESPOSTAS
(VALOR DE CADA QUESTÃO = 2 PONTOS)
Questão Resposta
30 40
senθ 0,6 cosθ 0,8
50 50
= = → = =
at atPsenθ F F 10 0,6 6N= → = × =
Pcosθ N N 10 0,8 8N= → = × =1
P = mg = 10 N
N
Fat
l = 50 cm
at
at
F 6
F μN μ 0,75
N 8
= → = = =
FA
FC
FB
2 2 2
C A BF F F= +
2 2 2
C X A X B X
2 2 2
C A B
Gm m Gm m Gm m
d d d
⎛ ⎞ ⎛ ⎞ ⎛ ⎞
= +⎜ ⎟ ⎜ ⎟ ⎜ ⎟
⎝ ⎠ ⎝ ⎠⎝ ⎠
2 2 4 4
C C CA
B B A B
m d dm
(9 16) 81 225
m m d d
⎛ ⎞ ⎛ ⎞ ⎛ ⎞ ⎛ ⎞
= × + = × + =⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟
⎝ ⎠ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠
2
C
B
m
15
m
=
E 100
i i 5A
R r 18 2
= → = =
+ +
1 1
2 2
Q L m Q 80 200 16000 cal
Q m c Δθ Q 200 1 20 4000 cal
= × → = × =
= × × → = × × =
1 2Q Q Q Q 16000 4000 20000 cal = 84000 J= + → = + =
3
2
3 2
3
Q 84000
p t Q R i t Q t 420 s 7 minutos
R i 200
× = → × × = → = = = =
×
R r
tgL r R tgL
h
−
= → = −
2
a
1 senL senL
senL tgL
n cosL 1 sen L
= → = =
−
2 2
a
a
a
2 2
a
1 1
tgL
n 11
n 1
n
1 36
r R 43 3
n 1 (1,345) 1
= =
−⎛ ⎞
−⎜ ⎟
⎝ ⎠
= − = − =
− −
4
d 2r d 6 cm= ⇒ =

2. 2/12/2007
Física
R C LΔV ΔV ΔV= +
R R C C L L C L R C C L LV γ Δθ V γ Δθ V γ Δθ (V V )γ V γ V γ= + ⇒ + = +
C
C C C CL R L R L R
LL R C R C L R C L
L
V μ μγ γ γ γ γ γ
V γ γ γ γ γ γ μ
μ
− − −
= → = → = ×
− − −
M
M
M M
5
5 3
C
5 3
L
(20 8) 10 6 10
9
(8 4) 10 2 10
−
−
− × ×
= × =
− × ×
M
M
T = 40 N
PA
= 100 N
A 2
A A
60
P T m a a 6m/s
10
− = ⇒ = =
T
PB
B B B BT P m a m (a g) T− = ⇒ + =
6
B
40
m 2,5kg
16
= =
p s s
s
p s
U U U100
U 250V
N N 300 750
= ⇒ = ⇒ =
eq eq
C C
C C C 8 F
2 2
= + ⇒ = = μ
2 6 2 4
2
T
CU 8 10 (2,5) 10
E 25 10 J
2 2
−
−× × ×
= = = ×
7
2T
C
E
E 6,25 10 J
4
−
= = ×
λ 0,5m=
λf=v8
400
f 800 Hz
λ 0,5
= = =
v
PV nRT= →
2PV 1,23 30
T T T 4,5 10 K
nR 1 0,082
×
= → = → = ×
×
Q mc T= Δ
9
3
Q = 4 2,42 900 8,7 10 cal× × = ×

3. 2/12/2007
Física
2
1
T P 16250 13000 3250
t 8s a 2,5m/s
m 1300 1300
− −
= ⇒ = = = =
1 1 1
2 2
1 1 1
v a t 2,5 8 20m / s
1 1
S a t 2,5 8 80m
2 2
= = × =
= = × × =
2 1
2 2
2
2
2 1 2 2 2
v 20
a 5m / s t 4s
a 5
1 1
S v t a t 20 4 5 16 40m
2 2
= ⇒ = = =
= − = × − × × =
10
1 2ΔS S S 80 40 120m= + = + =