Answer:
-3.396 m/s or 3.465 m/s
Explanation:
v = Speed of sound in air = 343 m/s
= Relative speed of the singer
f = Observed frequency
f' = Actual frequency
1% change can mean 
From the Doppler effect equation we have

The velocity is -3.396 m/s
when 

The velocity is 3.465 m/s
Answer:
E = 2.5 x 10⁻¹⁴ J
Explanation:
given,
diameter = 1.33 x 10⁻¹⁴ m
mass = 6.64 x 10⁻²⁷ kg
wavelength is equal to diameter
de broglie wavelength equal to diameter



v = 7.5 x 10⁶ m/s
Kinetic energy is equal to


E = 2.5 x 10⁻¹⁴ J
Answer:
T = 37.08 [N*m]
Explanation:
We must remember that torque is defined as the product of a force by a distance. This distance is measured from the point of application of force to the center of rotation of the rotating body.
The force is equal to the product of mass by gravitational acceleration.
![F=m*g\\F=70*9.81\\F=686.7[N]](https://tex.z-dn.net/?f=F%3Dm%2Ag%5C%5CF%3D70%2A9.81%5C%5CF%3D686.7%5BN%5D)
Now the torque can be calculated:
![T=F*r\\T=686.7*0.054\\T=37.08[N*m]](https://tex.z-dn.net/?f=T%3DF%2Ar%5C%5CT%3D686.7%2A0.054%5C%5CT%3D37.08%5BN%2Am%5D)