**Answer:**

F = 145 N

**Explanation:**

Given that,

Force applied by Jeff is 85 N and the force applied by Chris is 60 N. Both forces are acting in the same direction to push a rock up a hill. It means that net force is equal to the sum of these two forces.

So,

Net force on the rock = 85 N + 60 N

**= 145 N**

**Hence, the net force on the rock is 145 N.**

**Explanation:**

mass=kilogram,temperature=Klevin,power=watt,density=kilogram per cubic metre

**Answer:**

**Explanation:**

The **difference of electric potential** between two points is given by the formula , where <em>d</em> is the distance between them and<em> E</em> the electric field in that region, assuming it's constant.

The **electric field formula** is , where <em>F </em>is the force experimented by a charge <em>q </em>placed in it.

Putting this together we have , so we need to obtain the electric force the charged ball is experimenting.

On the second drop, the ball takes more time to reach the ground, this means that the electric force is opposite to its weight <em>W</em>, giving a net force . On the first drop only <em>W</em> acts, while on the second drop is <em>N</em> that acts.

Using the equation for **accelerated motion** (departing from rest) , so we can get the accelerations for each drop (1 and 2) and relate them to the forces by writting:

These relate with the forces by** Newton's 2nd Law**:

Putting all together:

Which means:

And finally we substitute:

Which for our values means:

First convection from the fire to the bar, then conduction from the bar to the hand

**Answer:**

Illegal drugs are dangerous because once someone starts doing drugs they go insane for more and their demand for my drugs can be so dangerous that they would even sometimes harm the people close to them and, In some cases people start to hate them selves and some even killed themselves.