Answer:
The velocity of the penny at 25th second is, v = 245 m/s
Explanation:
Given,
The time taken by the penny to hit the ground is, t = 30 s
The initial velocity of the penny, u = 0 m/s
The velocity of the penny at 25th second, v = ?
Using the II equation of motion, the displacement is given by the formula
<em> S = ut + ½ gt²</em>
= 0 + ½ x 9.8 ( 25²)
= 3062.5 m
Using the III equations of motion
<em>v² = u² + 2gs</em>
Substituting the given values,
v² = 0 + 2 x 9.8 x 3062.5
= 60025
v = 245 m/s
Hence, the velocity of the penny at 25th second is, v = 245 m/s
Power:
P= A/t
A = F · h = m · g · h
P = m · g · h / t, m = 7.5 kg, g = 9.81 m/s², h = 8.2 m, t = 1800 s
P = 7.5 · 9.81 · 8.2 / 1800 = 0.335 W
Answer:
3.6 kHz
Explanation:
The pipes behave like a closed pipe . The end open is the end of the air canal outside the ear and the closed end is the eardrum.
The first harmonic will be as seen in the figure attached.
The length of the first harmonic will be λ/4.
λ/4=2.4 cm
λ=2.4 * 4=9.6 cm 0.096 m
Speed of Sound- 344 m/s(in air)
velocity(v) * Time Period(T) = Wavelength (λ)
Also, Time Period(T)= \frac{\textrm{1}}{\textrm{Frequency(f)}}
\frac{\textrm{Velocity}}{\textrm{Wavelength}}=\frac{\textrm{1}}{\textrm{Time Period}} =Frequency
Plugging in the values into the equation,
Frequency = Hz
= 3583.3 Hz≈3600 Hz= 3.6 kHz
Frequency= 3.6 kHz
Answer: The recoil speed is - 8.9604. m/s.
Explanation: According to the Third Law of Newton, every action has an oppsite and equal reaction, and the Second Law of Newton, Force=mass·acceleration. Acceleration is a variation in velocity by any given time, so Force = mass·velocity·time.
Combining the two laws, there is : m1·v1 = - m2·v2. This is the Law of Conservation of Momentum.
Substituting and calculating:
v2 = - () · v1
v2 = - · 5.24.
v2 = - 8.9604.
The recoil speed of the thorium nucleus is - 8.9604.m/s.