Answer:
Explanation:
In order to measure the coefficient of friction , we apply external force to move the body . When external force comes in motion , we adjust the external force so that it moves with zero acceleration or uniform velocity . In this case external force becomes equal to kinetic frictional force and then net force becomes zero because
net force = mass x acceleration = m x 0 = 0
Now frictional force = μ mg where μ is coefficient of kinetic friction
so F = μ mg where F is external force applied
μ = F / mg
Hence , to make external force equal to frictional force , it is necessary to make acceleration of body zero .
Answer:

Explanation:
<u>Capacitance</u>
A two parallel-plate capacitor has a capacitance of

where

A = area of the plates = 
d = separation of the plates

We need to compute C. We'll use the circuit parameters for that. The reactance of a capacitor is given by

where w is the angular frequency

Solving for C

The reactance can be found knowing the total impedance of the circuit:

Where R is the resistance,
. Solving for Xc

The magnitude of the impedance is computed as the ratio of the rms voltage and rms current

The rms current is the peak current Ip divided by
, thus


Now collect formulas

Or, equivalently



The capacitance is now

The radius of the plates is

The separation between the plates is



Answer:
Norway, Sweden, Finland and Iceland
Explanation:
Sea ice is a frozen seawater that floats on the ocean surface. It is formed between the Antarctic and Arctic hemisphere. It disappears in summer but not completely. The countries that experienced sea ice in 1986 were eight (8) in number but the countries bordered by open water were in September 2017 were Norway, Iceland, Finland and Russia.
I think it’s A.) it explains why the universe is made up of matter
Answer:
225 N
Explanation:
"Below the horizontal" means he's pushing down at an angle.
Draw a free body diagram of the box. There are three forces: normal force N pushing up, weight force mg pulling down, and the applied force F at an angle θ.
Sum of forces in the y direction:
∑F = ma
N − mg − F sin θ = 0
N = F sin θ + mg
Plug in values:
N = (50 N) (sin 30°) + (20.0 kg) (10 m/s²)
N = 225 N