U = 0, the initial vertical velocity
Ignoring air resistance, with g set to 9.8 m/s².
The duration, t, required for the pen to reach a vertical speed of 19.62 m/s can be calculated with
19.62 m/s = 0 + (9.8 m/s²)*(t s)
t = 19.62/9.8 = 2.00 s
Result: 2.0 s
Answer:
The total energy can be expressed as 
Explanation:
The problem states that
The Poynting vector, which measures energy flux, equals 
The rectangle's length is represented by 
The width of the rectangle is
The duration considered is 
Mathematically, the overall electromagnetic energy incident on the area is given by

where A denotes the area of the rectangle, calculated as

By plugging in the respective values


Again substituting values


Δd = 23 cm. When the eta string of the guitar has nodes at both ends, the resulting waves create a standing wave, which can be expressed with the following formulas: Fundamental: L = ½ λ, 1st harmonic: L = 2 ( λ / 2), 2nd harmonic: L = 3 ( λ / 2), Harmonic n: L = n λ / 2, where n is an integer. The rope's speed can be calculated using the formula v = λ f. This speed remains constant based on the tension and linear density of the rope. Now, let's determine the speed with the provided data: v = 0.69 × 196, yielding v = 135.24 m/s. Next, we will find the wavelengths for the two frequencies: λ₁ = v / f₁, which gives λ₁ = 135.24 / 233.08, equaling λ₁ = 0.58022 m; λ₂ = v / f₂ results in λ₂ = 135.24 / 246.94, consequently λ₂ = 0.54766 m. We'll substitute into the resonance equation Lₙ = n λ/2. At the third fret, m = 3, therefore L₃ = 3 × 0.58022 / 2, resulting in L₃ = 0.87033 m. For the fourth fret, m = 4, which gives L₄ = 4 × 0.54766 / 2, equating to L₄ = 1.09532 m. The distance between the two frets is Δd = L₄ – L₃, so Δd = 1.09532 - 0.87033, leading to Δd = 0.22499 m or 22.5 cm, rounded to 23 cm.
Energy can be determined using the formula power multiplied by time, thus for a power of 1200 W (or 1200 Joules per second) and a duration of 30 seconds, the calculation yields 36000 J or 36 kJ of electrical energy.
If you need the electrical charge or current: Power equals voltage times current. Therefore, with a power of 1200 watts and a voltage of 120 V, the current can be found as 1200 W divided by 120 V, which results in 10 Amperes. The charge is obtained by multiplying 10 A by 30 s, yielding 300 C.
To counteract a 58 mph crosswind, the western component of the trajectory must be accounted for. Consequently, directing towards the northwest creates a 45-degree angle, aligning with the destination. This triangle's third vertex is located at the destination, with the right angle positioned there. The western aspect of their flight represents the triangle's base, while the vertical side reflects the resultant path, and the hypotenuse indicates the actual distance traveled. Since the 58 mph crosswind was countered by flying in a northwest direction, the distance from the starting point to the destination should equal the westward segment of their journey. The hypotenuse can be determined via the square root of twice the dimension of the identical sides.
c = sqrt (58^2 + 58^2) = sqrt (6728) = 82.02
An alternative method:
c = sqrt (2) * 58 = 1.414 * 58 = 82.02
Thus, they must fly at 82.02 mph.