The crest of one wave with an amplitude of 4 m meets up with the crest of a second
1 answer:
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Answer:
c.
Explanation:
- In absence of friction, total mechanical energy must be conserved.
- This means that the change in gravitational potential energy (in magnitude) must be equal to the change in kinetic energy:
- As it can be seen, the mass m is on the both sides of the equation, which means that it can be simplified.
- We can solve this equation for v (speed at the bottom) as follows:
- As it can be seen, the mass has no part in the equation, so, due both are starting from the same height, both people have the same speed at the bottom.
- The option c is the right one.
Answer:
a) t = 20 [s]
b) Can't land
Explanation:
To solve this problem we must use kinematics equations, it is of great importance to note that when the plane lands it slows down until it reaches rest, ie the final speed will be zero.
a)
where:
Vf = final velocity = 0
Vi = initial velocity = 100 [m/s]
a = desacceleration = 5 [m/s^2]
t = time [s]
Note: the negative sign of the equation means that the aircraft slows down as it stops.
0 = 100 - 5*t
5*t = 100
t = 20 [s]
b)
Now we can find the distance using the following kinematics equation.
x - xo = distance [m]
x -xo = (0*20) + (0.5*5*20^2)
x - xo = 1000 [m]
1000 [m] = 1 [km]
And the runaway is 0.8 [km], therefore the jetplane needs 1 [km] to land. So the jetpalne can't land