If the two waves combine to produce ANY wave that smaller
than either of the originals, that's destructive interference.
Answer:
a) t₁ = 4.76 s, t₂ = 85.2 s
b) v = 209 ft/s
Explanation:
Constant acceleration equations:
x = x₀ + v₀ t + ½ at²
v = at + v₀
where x is final position,
x₀ is initial position,
v₀ is initial velocity,
a is acceleration,
and t is time.
When the engine is on and the sled is accelerating:
x₀ = 0 ft
v₀ = 0 ft/s
a = 44 ft/s²
t = t₁
So:
x = 22 t₁²
v = 44 t₁
When the engine is off and the sled is coasting:
x = 18350 ft
x₀ = 22 t₁²
v₀ = 44 t₁
a = 0 ft/s²
t = t₂
So:
18350 = 22 t₁² + (44 t₁) t₂
Given that t₁ + t₂ = 90:
18350 = 22 t₁² + (44 t₁) (90 − t₁)
Now we can solve for t₁:
18350 = 22 t₁² + 3960 t₁ − 44 t₁²
18350 = 3960 t₁ − 22 t₁²
9175 = 1980 t₁ − 11 t₁²
11 t₁² − 1980 t₁ + 9175 = 0
Using quadratic formula:
t₁ = [ 1980 ± √(1980² - 4(11)(9175)) ] / 22
t₁ = 4.76, 175
Since t₁ can't be greater than 90, t₁ = 4.76 s.
Therefore, t₂ = 85.2 s.
And v = 44 t₁ = 209 ft/s.
I need more details like r u reading from something
<span>This is best understood with Newtons Third Law of Motion: for every action there is an equal and opposite reaction. That should allow you to see the answer.</span>
Answer:
Deltoid Force, 
Additional Information:
Some numerical information are missing from the question. However, I will derive the formula to calculate the force of the deltoid muscle. All you need to do is insert the necessary information and calculate.
Explanation:
The deltoid muscle is the one keeping the hand arm in position. We have two torques that apply to the rotating of the arm.
1. The torque about the point in the shoulder for the deltoid muscle, 
2. The torque of the arm, 
Assuming the arm is just being stretched and there is no rotation going on,
= 0
= 0
⇒ 
Where,
is radius of the deltoid
is the force of the deltiod
is the angle of the deltiod
is the radius of the arm
is the force of the arm , 
which is the mass of the arm and acceleration due to gravity
is the angle of the arm
The force of the deltoid muscle is,
but ,
∴
