Sin(90 + θ)
By addition angle formula for sine.
sin90cosθ + cos90sinθ
1*cosθ + 0*sinθ
cosθ + 0
= cosθ
sin(90 + θ) = cosθ
A substance which allows the un-interrupted flow of electric current is called an electric conductor
The two fields of study the principles of biomechanics come from physics and engineering. Biomechanics studies mechanical laws and living organisms. The correct answer is B.
The initial kinetic energy of the cart is

(1)
where m is the mass of the cart and v its initial velocity.
Then, the cart hits the spring compressing it. The maximum compression occurs when the cart stops, and at that point the kinetic energy of the cart is zero, so all its initial kinetic energy has been converted into elastic potential energy of the spring:

where k is the spring constant and x is the spring compression.
For energy conservation, K=U. We can calculate U first: the compression of the spring is x=60 cm=0.60 m, while the spring constant is k=250 N/m, so

So, the initial kinetic energy of the cart is also 45 J, and from (1) we can find the value of the initial velocity:
Answer:
Heat lost thru doors & windows = (100 - 75 - 5) = 20
20% is the fraction of heat lost thru doors and windows
One wants to obtain the largest savings per unit of cost
roof:
200 / 600 = 1/3
150 / 1000 = .15
40 / 2300 = .017
The largest of these is 1/3 so the most benefit would be obtained by insulating the roof
Since heat loss thru the roof depends on heat loss thru the attic, this is the most cost effective in reducing heat loss
The more the difference in temperature between the ceiling and roof (attic) the more heat will be lost thru the roof, so insulating the roof will decrease the heat loss of the attic