Answer:
0.0078 N
Explanation:
The electrostatic force between two charges is given by Coulomb's law:
where:
is the Coulomb's constant
are the two charges
r is the separation between the two charges
The force is attractive if the two charges have opposite sign, and repulsive if the two charges have same sign.
In this problem, we have:
located at 
located at 
located at 
The force between charge 1 and charge 2 is:

And since the two charges have opposite sign, the force is attractive, so the force on charge 1 is towards the right.
The force between charge 1 and charge 3 is:

And since the two charges have same sign, the force is repulsive, so the force on charge 1 is towards the left.
Therefore, the net force on charge 1 is:

towards the right.
Answer: If the woodpecker drums upon a tree 5 times in one second, then the frequency is 5 Hz; each drum must endure for one-fifth a second, so the period is 0.2 s.
To solve this problem we will apply the concepts related to magnetic flux and induced voltage. This last expression understood as the variation of the magnetic flux over time and, in turn, the magnetic flux expressed as the variation of the magnetic field in a certain area.
Magnetic flux through the circular coil is given as

The induced voltage is the change of the magnetic flux across the time, then

At the same time the magnetic flux through the square coil would be given as,

And the induced voltage EMF will be

Equating both expression we have



Therefore the emf induced in the square coil is 0.23355V
Gravitational Potential Energy, GPE = mgh
Where m is your mass in kg, g is acceleration due to gravity = 9.8 m/s², and h is the height in m.
The only value that be controlled here is the height h. The mass is constant, and acceleration due to gravity at that place is constant.
But h can be varied.
Hence to increase the gravitational potential energy between yourself and Earth is to increase the height h.
This can be done by climbing up a table, or climbing up a building through the stairs, or by using a lift.
Answer:
250N
Explanation:
weight = Mass(in kg) × Gravitational field strength
25 × 10 = 250N