Mathematics A
Find the value of sin 1110?
0.5
For very large n, which grows faster: n^2 or 2^n?
2^n
A light-year measures distance or time?
Distance
Which element of noble gases do not obey the octet rule?
Helium
What is the largest organ of the human body？
Skin 皮肤
How to calculate the sum of arithmetic seqence?
Assume there are n terms in arithmetic sequence, Sn=(a_1+a_n)*n/2
2,3,5,9,17,33,?
65
You are inside a smoothly moving train with no windows. If you drop a ball, does it fall straight down or backward?
Straight down
What is the product of complete combustion of diamond?
Carbon dioxide
What is jelly-like substance filling the interior of the cell and holds the organelles？
Cytoplasm 细胞质
Describe the phase shift of sin (2x+pi/2)
-pi/4
Which is larger, 0.999... or 1?
0.999... =0.333...*3 = (1/3) *3 = 1
If you see lightning and hear thunder 3 seconds later, approximately how far away is the lightning?
About 1 km. 3s * 340 m/s = 1020 m
Which elements has the highest value of electronegativity?
Fluorine
What is the process that creates two identical daughter cells from one parent cell？
Mitosis 有丝分裂
Find the limit: when t approaches to infinite what is the value of (t^3-8)^(1/3)/(2t)
0.5
You have 1000 kg of mushrooms, which are 99% water by mass.
After several days of drying, the mushrooms become 98% water by mass.
Assuming only water is lost and the dry mass remains constant,
How much water has been evaporated（蒸发）?
500kg；
0.02M=10
水=500−10=490kg
Δm=990−490=500kg
A small particle is released from rest at a height h above the lowest point of a smooth vertical circular track of radius R. The particle then enters and moves along the inside of the track.
The motion is smooth and frictionless. Find the minimum height h such that the particle just maintains contact with the track and successfully passes through the highest point of the circle without losing contact.
Express your answer in terms of R.
2.5R
Which element has the longest name in Period 2?
Beryllium
This enzyme unwinds the DNA double helix during replication.
Helicase DNA解旋酶
Define the motion function of a Ferris wheel by following condition. Write the function h in terms of t
1. A Ferris wheel has a diameter of 400 feet
2. it takes 30 seconds to make one complete revolution.
3.Let height at the center of the wheel represent the height at time 0.
h(t)=200sin[(pi/15)*t]
What is the last digit of 7^2026
9
because it has a period of 4. （7, 9, 3, 1）
A uniform light rod AB of length L = 2.0 m and weight 20 N is hinged at point A to a vertical wall. The rod is held in equilibrium by a light inextensible string attached at point B to the wall.
The rod is inclined at an angle of 30° to the horizontal, and the string is perpendicular to the rod.
Determine the magnitude of the tension T in the string.
T = 5\sqrt{3}N ≈ 8.66N
What is the lightest metal?
Lithium
This marine animal has three hearts, “nine brains”, and blue blood, but despite all that brainpower, it has no sense of hearing.
Octopus 章鱼