A group of tourists drives through a state park in Maine. While arguing about whether the animal they've just seen is an Elk or
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Answer:
49 N
Explanation:
In order to move the box at constant speed, the acceleration of the box must be zero (a=0): this means, according to Newton's second law,
F = ma
that the net force acting on the box, F, must be zero as well.
Here there are two forces acting on the box in the horizontal direction while it is moving:
- The force of push applied by the guy, F
- The frictional force,
For an object moving on a flat surface, the frictional force is given by
where
is the coefficient of friction
m is the mass of the box
g is the acceleration of gravity
So the equation of the forces becomes
And substituting:
We find the force that must be applied by the guy:
Answer:
20.60 kV
Explanation:
Capacitance of parallel plates without dielectric between them is:
with d the distance between the plates, A the area of the plates and ε₀ the constant , so :
But the dielectric constant is defined as:
With C the effective capacitance (with the dielectric) and Co the original capacitance (without the dielectric). So, the new capacitance is:
But capacitance is related with voltage by:
with Q the charge and V the voltage, using the new capacitance and solving for V: