Difference between Gravitational Force and Electrostatic Force
Force is just defined as a push or pull of an object with the mass that causes it to change its velocity. It is an external agent that is capable of changing the state of a particular body neither in a rest position nor in motion. It has both magnitude and direction. It can be measured using a spring balance. The formula of force is F = ma, where m = mass of the object, a = acceleration.
Both Gravitational force and Electrostatic force are examples of Non-Contact forces. Non-Contact forces are defined as the force that acts through spaces without making any direct contact with the body.
Gravitational Force
Gravitational Force is defined as the force by which the earth attracts another object by mass. It is the force of attraction between all the masses in the universe, i.e. the attraction of the earth’s mass to bodies near its surface. Gravitational Force is the force that attracts any two objects with the mass
Formula of Gravitational Force
F = (G m_{1}m_{2})/r^{2}
Where,
G = Gravitational constant = 6.67 × 10^{-11} N. m^{2}/kg^{2}
m_{1 }= mass of the object 1.
m_{2} = mass of the object 2.
r = distance between two objects.
S.I units = Newton (N).
Electrostatic Force
It is defined as a force between objects due to the charge of the objects. It is the force exerted by a charged body on another charged body or an uncharged body. It is the force that comes when the bodies are not in contact. It is also defined as the attractive or repulsive force between two objects that are caused by their electric charge. It is also called Coulomb Force.
Formula of Electrostatic Force
F = (kq_{1}q_{2})/r^{2}
Where,
k = proportionality constant = 1/4π€_{o}
Where €_{o }= permittivity of a vacuum= 9 × 109 N.m^{2}/c^{2}.
q_{1 }= charge of the object 1.
q_{2} = charge of the object 2.
r = distance between the two objects.
Difference between Gravitational Force and Electrostatic Force
Gravitational Force | Electrostatic Force | |
1. | It is the force by which earth attracts another object by its mass. | It is the force of an object due to its charge. |
2. | The force due to gravity does not depend on the medium. | It depends on the medium (charge). |
3. | It is the only attractive force. | It is both attractive as well as a repulsive force. |
4. | Formula: F = (G m_{1}m_{2})/r^{2} | Formula: F = (kq_{1}q_{2})/r^{2} |
5. | It has a gravitational constant (G). | It has a proportionality constant (k). |
6. | It originates from the mass of the object. | It originates from the charge of the object. |
Sample Questions
Question 1: How much force is required to accelerate a 2000kg car at 5m/s^{2}?
Answer:
Given that,
mass of the car (m) = 2000kgs.
acceleration (a) = 5 m/s^{2}.
F = ma
F = 2000 × 5
F = 10000 N.
Therefore, the force required is 10000 N.
Question 2: Two objects of mass 1000kg and 500 kg are kept at a distance of 400. Find the force of attraction between them
Answer:
Given that,
m_{1}= 1000kg
m_{2 }= 500m
r = 400m
F = G m_{1}m_{2}/r^{2}
= (6.67 × 10^{-11}) × (1000 × 500)/(400)^{2}
= (6.67 × 10^{-11}) × 50/16
= 2.08 × 10^{-10} N.
Therefore, the force of attraction between them is 2.08 x 10^{-10} N.
Question 3: Two charges 3C and 6 C are kept at a distance of 9m away from each other. Find the force of attraction between them?
Answer:
Given that,
q_{1}= 3C
q_{2 }= 6C
r = 9m
F = k.q_{1}q_{2}/r^{2}
F = (9 × 10^{9} × 3 × 6)/9^{2}
F= 2 × 10^{9} N.
Therefore, the force of attraction between them is 2 × 10^{9} N.
Question 4: Let us suppose 2 satellites are passing around the orbit, earth close to each other. For a moment they are part of each other if 400m. The masses of the satellite are 400kg and 1200kg. Calculate the gravitational force between them?
Answer:
Given that,
m_{1 }= 400kg
m_{2 }= 1200kg
r = 400m
F = (6.67 × 10^{-11} × 400 × 1200)/(400)^{2}
F = 20.01 × 10^{-11} N.
Therefore, the gravitational force between is 20.01 × 10^{-11}N.
Question 5: A body of charges 10 C and 30C are kept at a distance of 10m away from each other. Find the electrostatic force between them?
Answer:
Given that,
q_{1} = 10C
q_{2 }= 30C
r = 10m
F = (9 × 10^{9} × 10 × 30)/(10)^{2}
F = 27 × 10^{9} N.
Therefore, the electrostatic force between them is 27 × 10^{9} N.
Question 6: An object having a mass of 2 kg is moving with a speed of 8 m/s hits a wall and comes to rest for 10sec. Calculate the force that makes the object stop.
Answer:
Given that,
m = 2 kg
Initial velocity u = 8 m/s
Final velocity v = 0 m/s
Time = 10 sec.
Acceleration a = ( v – u)t
a = (0 – 8)10
a = 80
F = 2 × 80
F = 160 N.
Therefore, the force that is needed to stop the object = 160 N.