Solve for angles A-D
1 answer:
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(a) 29.8 m/s
To solve this problem, we start by analyze the vertical motion first. This is a free fall motion, so we can use the following suvat equation:
where, taking upward as positive direction:
is the final vertical velocity
is the initial vertical velocity (zero because the pebble is launched horizontally)
is the acceleration of gravity
s = -25.0 m is the displacement
Solving for vy,
(downward, so we take the negative solution)
The pebble also have a horizontal component of the velocity, which remains constant during the whole motion, so it is
So, the final speed of the pebble as it strikes the ground is
(b) 29.8 m/s
In this case, the pebble is launched straight up, so its initial vertical velocity is
So we can find the final vertical velocity using the same suvat equation as before:
(downward, so we take the negative solution)
The horizontal speed instead is zero, since the pebble is initially launched vertically, so the final speed is just equal to the magnitude of the vertical velocity:
v = 29.8 m/s
(c) 29.8 m/s
This case is similarly to the previous one: the only difference here is that the pebble is launched straight down instead than up, therefore
Using again the same suvat equation:
(downward, so we take the negative solution)
As before, the horizontal speed instead is zero, since the pebble is initially launched vertically, so the final speed is just equal to the magnitude of the vertical velocity:
v = 29.8 m/s
We notice that the final value of the speed is always the same in all the three parts, so it does not depend on the direction of launching. This is due to the law of conservation of energy: in fact, the initial mechanical energy of the pebble (kinetic+potential) is the same in all three cases (because the height h does not change, and the speed v does not change either), and the kinetic energy gained during the fall is also the same (since the pebble falls the same distance in all 3 cases), therefore the final speed must also be the same.
Answer:
each resistor is 540 Ω
Explanation:
Let's assign the letter R to the resistance of the three resistors involved in this problem. So, to start with, the three resistors are placed in parallel, which results in an equivalent resistance defined by the formula:
Therefore, R/3 is the equivalent resistance of the initial circuit.
In the second circuit, two of the resistors are in parallel, so they are equivalent to:
and when this is combined with the third resistor in series, the equivalent resistance () of this new circuit becomes the addition of the above calculated resistance plus the resistor R (because these are connected in series):
The problem states that the difference between the equivalent resistances in both circuits is given by:
so, we can replace our found values for the equivalent resistors (which are both in terms of R) and solve for R in this last equation: