Forces in the universe that act over long distance, meaning the distance is greater than the diameter of the nucleus of the atom are:
1. Electrostatic force or Coulomb force: Fc=(k*Q₁*Q₂)/r²,
2. Gravitational force: Fg=(G*m₁*m₂)/r²,
3. Magnetic force: Fm=qvB,
4. London dispersion force, also known as one of the van der Waals forces.
The mass of the quarterback is 61.2 kg.
Explanation:
mass of the football player = m1 = 102 kg
mass of the quarterback = m2 = ?
velocity of the football player = v1 = 8 m/s
According to the law of conservation of momentum:
The total momentum of a system before and after the collision remains constant. Assuming the situation as an isolated system which is not affected by any external factors, we have:
m₁v₁ + m₂v₂ = (m₁+m₂)V
Here, we need to find m₂.
We assume that the quarterback is standing still when he is attacked by the football player so v₂ = 0 m/s
After the collision both of them fall to the ground with a velocity of 5 m/s so V = 5 m/s

Keywords: momentum, velocity, law of conservation of momentum
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Answer:
E1 = 10.15 * 10^4 N/C
E2 = 0
E3 = 10.15 *10^4 N/C
Explanation:
Given data:
Two 13 cm-long thin glass rods ( L ) = 0.13 m
charge (Q) = +11nC
distance between thin glass rods = 4 cm .
<u>Calculate the electric field strengths </u>
electric charge due to a single glass rod in the question ( E ) = 
equation 1 can be used to determine E1, E2 and E3 because the points lie within the two rods hence the net electric field produced will be equal to the difference in electric fields produced
applying equation 1 to determine E1
E1 =
( distance from 1 rod is 0.01 m and from the other rod is 0.03 )
= 
= 10.15 * 10^4 N/C
applying equation 1 to determine E2
E2 = 

therefore E2 = 0
E1 = E3
hence E3 = 10.15*10^4 N/C
Answer:
A
B

C

D

Explanation:
Considering the first question
From the question we are told that
The spring constant is 
The potential energy is 
Generally the potential energy stored in spring is mathematically represented as 
=>
=>
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Considering the second question
From the question we are told that
The mass of the dart is m = 0.050 kg
Generally from the law of energy conservation

=> 
=> 
Considering the third question
The height at which the dart was fired horizontally is 
Generally from the law of energy conservation

Here KE is kinetic energy of the dart which is mathematical represented as

=> 
=> 
=> 
Considering the fourth question
Generally the total time of flight of the dart is mathematically represented as

=> 
=> 
Generally the horizontal distance from the equilibrium position to the ground is mathematically represented as

=> 
=> 