Answer:
Q = - 256 X 10⁻⁷ C .
Explanation:
Electric field due to a charge Q at a distance d from the center is given by the expression
E = k Q /d² Where k is a constant and it is equal to 9 x 10⁹
Put the given value in the equation
9 x 10² = 
Q = 
Q = - 256 X 10⁻⁷ C .
It will be negative in nature as the field is directed towards the center.
Answer:
The correct option is;
The acceleration remains constant
Explanation:
The acceleration is due to the force of gravitational attraction between the text book and the Earth
According to Newton's law of gravitation, there is an attractive force between all objects given by the following relation;
F = G×M₁×m₂/r²
Where;
G, M₁, m₂, and r are constant such that we have;
G×M₁/r² = Constant = The acceleraton due to gravity, g
F = g×m₂
So the acceleration of the textbook as it is being attracted by the force of gravity towards the ground (Earth) is remains constant.
Friction can be reduced by making a surface smooth. It can also be reduced by applying lubricants such as oil and grease
Power is the rate at which work is done (2nd option)
