By definition,
q = 1.22y/D
Where,
q = min. angle
y = wavelength
D = Aperture diameter = diameter of the antenna
At distance "x" from the antenna,
L =xq = 1.22xy/D
Where, L = Min. distance
But, y =c/f = (3*10^8)/(16*10^9) = 0.01875 m
Substituting;
L = 1.22*5*10^3*0.01875/2.1 = 54.46 m
M = 30 g = 0.03 kg, the mass of the bullet
v = 500 m/s, the velocity of the bullet
By definition, the KE (kinetic energy) of the bullet is
KE = (1/2)*m*v²
= 0.5*(0.03 kg)*(500 m/s)² = 3750 J
Because the bullet comes to rest, the change in mechanical energy is 3750 J.
The work done by the wall to stop the bullet in 12 cm is
W = (1/2)*(F N)*(0.12 m) = 0.06F J
If energy losses in the form of heat or sound waves are ignored, then
W = KE.
That is,
0.06F = 3750
F = 62500 N = 62.5 kN
Answer:
(a) 3750 J
(b) 62.5 kN
Answer:
225 rpm
Explanation:
The angular acceleration of the fan is given by:
where
is the final angular speed
is the initial angular speed
is the time interval
For the fan in this problem,
Substituting,
Now we can find the angular speed of the fan at the end of the 5th second, so after t = 5 s. It is given by:
where
Substituting,
