Full Question
A 10 kilogram object suspended from the end of a vertically hanging spring stretches the spring 9.8 centimeters. At time t = 0, the resulting mass—spring system is disturbed from its rest state by the force F (t) = 20 cos(8t). The force F (t) is expressed in Newtons and is positive in the downward direction, and time is measured in seconds.
Determine the spring constant k.
Answer:
Spring Constant = 1000Nm^-1
Step-by-step explanation:
Given
Mass = 10kg
Spring Extension = 9.8cm
Spring Constant K = Force/Extension
Force = Mass * Acceleration
Force = 10 * 9.8 = 9.8N
Spring Extension = 9.8 cm = 9.8 /100 = 0.098 m
Spring constant = 98 / 0.098
Spring Constant = 1000Nm^-1
Answer:
the second one
Step-by-step explanation:
i did it in my head and double checked :)
Answer:
B. y = 2x - 9
Step-by-step explanation:
All of the answer choices has a slope of 2, but B is the only answer choice that has (4,-1) on its line.
You can tell by plugging the point into the equation and seeing if the result is true.
y = 2x - 9
-1 = 2(4) - 9
-1 = 8 - 9
-1 = -1
Answer:
log8 (2.718) = 0.48
Step-by-step explanation:
In 2.718 ÷ In 8 = 0.999896 ÷ 2.07944
= 0.4808
Answer: 490 grams of the first alloy should be used.
30 grams of the second alloy should be used.
Step-by-step explanation:
Let x represent the weight of the first alloy in grams that should be used.
Let y represent the weight of the second alloy in grams that should be used.
A chemist has two alloys, one of which is 15% gold and 20% lead. This means that the amount of gold and lead in the first alloy is
0.15x and 0.2x
The second alloy contains 30% gold and 50% lead. This means that the amount of gold and lead in the second alloy is
0.3y and 0.5y
If the alloy to be made contains 82.5 g of gold, it means that
0.15x + 0.3y = 82.5 - - - - - - - - - - - -1
The second alloy would also contain 113 g of lead. This means that
0.2x + 0.5y = 113 - - - - - - - - - - - - -2
Multiplying equation 1 by 0.2 and equation 2 by 0.15, it becomes
0.03x + 0.06y = 16.5
0.03x + 0.075y = 16.95
Subtracting, it becomes
- 0.015y = - 0.45
y = - 0.45/- 0.015
y = 30
Substituting y = 30 into equation 1, it becomes
0.15x + 0.3 × 30 = 82.5
0.15x + 9 = 82.5
0.15x = 82.5 - 9 = 73.5
x = 73.5/0.15
x = 490
