The motion described here is a projectile motion which is characterized by an arc-shaped direction of motion. There are already derived equations for this type of motions as listed:
Hmax = v₀²sin²θ/2g
t = 2v₀sinθ/g
y = xtanθ + gx²/(2v₀²cos²θ)
where
Hmax = max. height reached by the object in a projectile motion
θ=angle of inclination
v₀= initial velocity
t = time of flight
x = horizontal range
y = vertical height
Part A.
Hmax = v₀²sin²θ/2g = (30²)(sin 33°)²/2(9.81)
Hmax = 13.61 m
Part B. In this part, we solve the velocity when it almost reaches the ground. Approximately, this is equal to y = 28.61 m and x = 31.91 m. In projectile motion, it is important to note that there are two component vectors of motion: the vertical and horizontal components. In the horizontal component, the motion is in constant speed or zero acceleration. On the other hand, the vertical component is acting under constant acceleration. So, we use the two equations of rectilinear motion:
y = v₀t + 1/2 at²
28.61 = 30(t) + 1/2 (9.81)(t²)
t = 0.839 seconds
a = (v₁-v₀)/t
9.81 = (v₁ - 30)/0.839
v₁ = 38.23 m/s
Part C.
y = xtanθ + gx²/(2v₀²cos²θ)
Hmax + 15 = xtanθ + gx²/(2v₀²cos²θ)
13.61 + 15 = xtan33° + (9.81)x²/[2(30)²(cos33°)²]
Solving using a scientific calculator,
x = 31.91 m
-- "Declination zero" means the object is in the sky at some point directly over the Earth's equator.
-- If it's the sun and it appears to be over the equator, then that tells us that the Earth's axis is not tilted toward or away from it.
-- That in turn tells us that the Earth is at one of the two equinoxes in its orbit, either the Spring one or the Autumn one. <em> (D)</em>
-- (The first days of Summer and Winter coincide with solstices, not equinoxes.)
Is the number the whole thing equal to 1?
Complete question is The frequency of the fundamental of the guitar string is 320 Hz. At what speed c do waves move along that string? wavelength is 40 cm.
Answer:
128 m/s
Explanation:
In case where fundamental frequency is given, the speed with waves travel along the string can be calculated using the following formula:
v = f (2L) where L is the length of the string (L = λ/2)
⇒v= f λ
f = 320 Hz (given)
λ = 40 cm = 0.40 m
Substitute the values:
⇒ v = 320 Hz × 0.40 m= 128 m/s