Round 1
Tuesday, September 15, 2015
HighFour Physics
Category C: Grades 9 – 10
The use of calculator is required.
Answer #1:
Explanation:
Weight
Weight is the resultant gravitational force acting on the body as influenced
by all other bodies in space. Weight is a vertical force that almost always
acts downward.
Answer #2:
Solution:
241.5
Simply use the trigonometric function cosine to solve for Fx; cos θ =
FX
cos 15° =
250 lb
FX
F
.
Fx = 241.4815 ≅ 241.5 lbs
Answer #3:
Calorie
Answer #4:
Explanation:
Precision
Precision is also the measure of consistency of measurements. It is different
from accuracy which is the degree of exactness of a measurement
compared to the expected value.
Answer #5:
Solution:
320.9
To determine amount of water (gal) it can hold, use V = L x W x H
Convert all variables into common unit to achieve dimensional
homogeneity.
3 ft
L = 10 yd �
� = 30 ft
1 yd
W = 192 in �
1 ft
� = 16 ft
12 in
V = (30 ft)(16 ft)(5 ft) = 2400 ft3
V = 2400 ft 3 �
1gal
� = 320.8556 ≅ 320.9 gal
7.48ft 3
Round 1
Tuesday, September 15, 2015
HighFour Physics
Category C: Grades 9 – 10
The use of calculator is required.
Answer #6:
Solution:
240 W
Assume East is positive (+) and West is negative (-):
R = (+150 m) + (-230 m) + (-300 m) + (+620 m) + (-480 m)
R = - 240 m
R = 240 m West
Answer #7:
Green
Answer #8:
Frequency
Answer #9:
Trough
Reference Image:
Crest
Trough
Answer #10:
5.2
Solution:
Use the formula: x = �
90.0 m = �
vi +vf
2
vi + 12.8
� 10 s
2
�t
Solving for vi will yield 5.2 meters/second
Answer #11:
Isaac Newton
Round 1
Tuesday, September 15, 2015
HighFour Physics
Category C: Grades 9 – 10
The use of calculator is required.
Answer #12:
Solution:
20
R
Firstly, use R = vixt and manipulate to arrive at vx = to solve for vix.
t
45 m
m
= 15
vix =
3s
s
Solve for angle, α:
m
15
vix
s
α = cos −1 � � = cos −1 � m
� = 53.1301°
vi
25
s
Answer #13:
Solution:
Next, solve for viy :
m
𝑚𝑚
𝑣𝑣𝑖𝑖𝑖𝑖 = �25 � (sin 53.1301) = 20
s
𝑠𝑠
17.7
Use the formula ∆P = ρgh
m
kg
∆P = (1.06) �1000 3 � �9.8 2 � (1.7 m) = 17,659.6 Pa
s
m
1kPa
∆P = 17,659.6 Pa �
� = 17.6596 kPa ≈ 17.7 kPa
1000Pa
Answer #14:
Calorimeter
Answer #15:
Convex
Answer #16:
Explanation:
Regular
Reflection of light is regular if angles of incidence and the angles of
reflection are equal.
Round 1
Tuesday, September 15, 2015
HighFour Physics
Category C: Grades 9 – 10
The use of calculator is required.
Answer #17:
358.4
Solution:
Use the formula: 𝑇𝑇 = 2𝜋𝜋�
𝐿𝐿
𝑔𝑔
100 vibrations
150 cm
= 2π�
246 seconds
g
Solving for g will yield 35,836.14 cm·s-2
1m
= 358.3614 m� 2 ≅ 358.4 m� 2
35,836.14 cm� 2 �
s 100 cm�
s
s
Answer #18:
Elasticity
Answer #19:
Solution:
3.6
1
First, use the formula: y = viy + gt 2
2
Since the ball only traveled along the horizontal, viy is 0: y =
1
m
0.75m = �9.8 2 � t 2
2
s
1
2
gt 2
Solving for time will yield 0.391 seconds. Substitute the calculated time in:
𝑅𝑅 = 𝑣𝑣𝑥𝑥 𝑡𝑡
Answer #20:
Solution:
vx = v i =
1.4m
m
= 3.58 ≅ 3.6
0.391s
s
338.33
Use the formula V = 331 + 0.6T
Convert first 54°F to °C
5
°𝐶𝐶 = (54° − 32°) = 12.2222 m/s
9
m
V = 331 + 0.6 �12.2222 �
s
V = 338.33
m
s