If you are sitting on a school bus, is the driver in motion (according to your
1 answer:
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Answer:
a. Vf = 39.24 [m/s]
b. Vf = 31.24 [m/s]
c. Vf = 47.24 [m/s].
Explanation:
To solve this problem we can use the following equation of kinematics. We have to keep in mind that the gravitational acceleration acts downwards, therefore when the rock falls towards the abyss it has the same direction of the acceleration and that is why the gravitational acceleration has a positive sign in the equation.
where:
Vf = final velocity [m/s]
Vo = initial velocity = 0 (when the rock is dropped)
g = gravitational acceleration = 9.81 [m/s²]
t = time = 4 [s]
a.
b.
In this particular situation, the acceleration will be taken as negative because the gravity is pointing in the opposite direction of the movement of the rock.
The negative sign in the answer tells us that the rock no longer moves up instead it does downwards when 4 seconds have passed.
c.
Answer:
x = 41.2 m
Explanation:
The electric force is a vector magnitude, so it must be added as vectors, remember that the force for charges of the same sign is repulsive and for charges of different sign it is negative.
In this case the fixed charges (q₁ and q₂) are positive and separated by a distance (d = 100m), the charge (q₃ = -1.0 10⁻³ C)) is negative so the forces are attractive, such as loads q₃ must be placed between the other two forces subtract
F = F₁₃ - F₂₃
let's write the expression for each force, let's set a reference frame on the charge q1
F₁₃ =
F₂₃ =
they ask us that the net force be zero
F = 0
0 = F₁₃ - F₂₃
F₁₃ = F₂₃
k \frac{q_1 q_3}{x^2} =k \frac{q_2 q_3}{(d-x)^2}
q1 / x2 = q2 / (d-x) 2
(d-x)² = x²
we substitute
(100 - x)² = 2/1 x²
100- x = √2 x
100 = 2.41 x
x = 41.2 m