Answer:
171.5 N
Explanation:
The gravitational force on an object due to the Earth is given by

where
m is the mass of the object
g is the acceleration due to gravity
The acceleration due to gravity at a certain height h above the Earth is given by

where:
G is the gravitational constant
is the Earth's mass
is the Earth's radius
Here,

So the acceleration due to gravity is

We know that the mass of the object is
m = 70 kg
So, the gravitational force on it is

Answer:

Explanation:
We are given that
Surface area of membrane=
Thickness of membrane=
Assume that membrane behave like a parallel plate capacitor.
Dielectric constant=5.9
Potential difference between surfaces=85.9 mV
We have to find the charge resides on the outer surface of membrane.
Capacitance between parallel plate capacitor is given by

Substitute the values then we get
Capacitance between parallel plate capacitor=

V=


Hence, the charge resides on the outer surface=
Answer: 134 neutrons are there in the nucleus of Radon-220
Explanation:
Atomic number : It is defined as the number of electrons or number of protons present in a neutral atom.
Thus, number of protons = atomic number = 86
Mass number is the number of the entities present in the nucleus which is the equal to the sum of the number of protons and electrons.
Mass number = Number of protons + Number of neutrons
220 = 86 + Number of neutrons
Number of neutrons = 134
Answer:
Friction can be minimized by using lubricants like oil and grease and by using ball bearing between machine parts. A substance that is introduced between two surfaces in contact, to reduce friction, is called a lubricant. Fluid friction can be minimized by giving suitable shapes to the objects moving in the fluids.
Explanation:
hope it helps