Newton's third law says:
"<span>For every action, there is an equal and opposite reaction. ".
So, the force that Tom does on the sister is equal to force the sister applies on Tom:
</span>

<span>where the label "t" means "on Tom", while the label "s" means "on the sister".
From Newton's second law, we also know
</span>

where m is the mass and a the acceleration. <span>so we can rewrite the first equation as
</span>

<span>And find Tom's acceleration:
</span>

<span>
</span>
Answer:
The torque on the child is now the same, τ.
Explanation:
- It can be showed that the external torque applied by a net force on a rigid body, is equal to the product of the moment of inertia of the body with respect to the axis of rotation, times the angular acceleration.
- In this case, as the movement of the child doesn't create an external torque, the torque must remain the same.
- The moment of inertia is the sum of the moment of inertia of the merry-go-round (the same that for a solid disk) plus the product of the mass of the child times the square of the distance to the center.
- When the child is standing at the edge of the merry-go-round, the moment of inertia is as follows:

- When the child moves to a position half way between the center and the edge of the merry-go-round, the moment of inertia of the child decreases, as the distance to the center is less than before, as follows:

- Since the angular acceleration increases from α to 2*α, we can write the torque expression as follows:
τ = 3/4*m*r² * (2α) = 3/2*m*r²
same result than in (2), so the torque remains the same.
Answer:
Given the potential, 
The components of the electric field are:


Let's calculate the potential difference for all given points.



Solving for A, we have:



Solving for B, we have:


Solving for C, we have:

For all given points, let's calculate the magnitude of electric field as follow:


Solving for l, we have:

From above, A = -6




Solving for m, we have:

From above, B = -4



Solving for n, we have:

From above, C = -2

Explanation:it is beause they are sharper and also have less surface area and therefore more pressure
Answer:
C) rift valley
Explanation:
A rift valley is a lowland region formed by the interaction of Earth's tectonic plates. This small rift valley has a typical formation—long, narrow, and deep. It was formed by the Thingvellir rift, where the North American and Eurasian tectonic plates are tearing, or rifting, apart over a hotspot on the island of Iceland.