Answer: 0.61
Explanation:
This is calculation based on friction.
Since the box rests on a flat surface, the force that exists between them is known as frictional force.
Since the friction is dynamic (velocity is not zero)
The frictional force = kinetic energy gained by the body.
Ff = 1/2mv^2
coefficient of kinetic friction × normal reaction = 1/2mv^2
Since normal reaction is equal to the weight(force acting along the vertical component)
Normal reaction= mg = 50 × 10 = 500N. Therefore,
coefficient of kinetic friction × 500 = 1/2×50×3.5^2
coefficient of kinetic friction = 50×3.5^2/1000
coefficient of kinetic friction= 0.61
Answer:

Explanation:
Let assume that ball begins its movement at a height of zero. The height can be found by energy approach, to be precise, by Principle of Energy Conservation:


Answer:
0.08 N/C
Explanation:
Electric Field: This is defined as the force per unit charge exerted at a point. The expression for electric field is given as,
E = Kq/r².............................. Equation 1
Where E = Electric Field, q = Charge, k = proportionality constant, r = distance.
making q the subject of the equation,
q = Er²/k............................... Equation 2
Given: E = 2 N/C, r = 4 m,
Substitute into equation 2
q = 2(4)²/k
q = 32/k C.
When r is increased to 20 m,
E = k(32/k)/20²
E = 32/400
E = 0.08 N/C.
Hence the electric Field = 0.08 N/C