Answer:
z = 0.8 (approx)
Explanation:
given,
Amplitude of 1 GHz incident wave in air = 20 V/m
Water has,
μr = 1
at 1 GHz, r = 80 and σ = 1 S/m.
depth of water when amplitude is down to 1 μV/m
Intrinsic impedance of air = 120 π Ω
Intrinsic impedance of water = 
Using equation to solve the problem

E(z) is the amplitude under water at z depth
E_o is the amplitude of wave on the surface of water
z is the depth under water



now ,


taking ln both side
21.07 x z = 16.81
z = 0.797
z = 0.8 (approx)
The ball rolled a distance of
d = 12m + 20m.
But the change of position is
x = + 12m - 20m
Answer:
d = 69 .57 meter
Explanation:
First case
Speed of car ( v ) = 20.5 mi/h = 9.164 M/S
distance ( d ) = 11.6 meter ( m = mass of the car )
Work done = 0.5 m v² = 0.5 * 9.164² * m J = 41.99 m J
Force = ( workdone /distance ) = ( 41.99 m / 11.6 ) = 3.619 m N
Second case
v = 50.2 mi/h = 22.44135 m/s
d = ?
Work done = 0.5 * 22.44² * m J = 251.7768 * m J
Since the braking force remains the same .
3.619 m = ( 251.7768 m / d )
d = 69 .57 meter
Answer:
<h2>42.67N</h2>
Explanation:
Step one:
<u>Given </u>
mass m= 0.32kg
intital velocity, u= 14m/s
final velocity v= 22m/s
time= 0.06s
Step two:
<u>Required</u>
Force F
the expression for the force is
F=mΔv/t
F=0.32*(22-14)/0.06
F=(0.32*8)/0.06
F=2.56/0.06
F=42.67N
The average force exerted on the bat 42.67N
Answer:
Friction force on the bullet is 58.7 N opposite to its velocity
Explanation:
As we know that initial speed of the bullet is 55 m/s
after travelling into the sand bag by distance d = 1.34 m it comes to rest
so final speed

now we can use kinematics top find the acceleration of the bullet

so we have


now by Newton's II law we know that

so we have

