Answer:
1362000 kgm/s
Explanation:
So the total mass combination of the plane and the people inside it is
M = 35000 + 160*65 = 45400 kg
After 15 seconds at an acceleration of 2 m/s2, the plane speed would be
V = 2*15 = 30 m/s
So the magnitude of the plane 15s after brakes are released is
MV = 45400 * 30 = 1362000 kgm/s
Mechanical Energy = PE + KE
PE: mgh = 200 x 9.8 x 18 = 35280
PE: 35280 Joules
KE: 1/2mv^2 = 1/2 x 200 x 16^2 = 25600
KE: 25600 Joules
ME: 35280 + 25600
ME: 60,880J
The velocity of the brick is 39.2 m/s downward
Explanation:
The motion of the brick is a free fall motion, since the object is affected only by the force of gravity. Therefore, it has a uniformly accelerated motion towards the ground, with constant acceleration of
.
So, we can find its velocity using the suvat equation:

where
v is the final velocity
u is the initial velocity
a is the acceleration
t is the time
For the brick in this problem (taking downward as positive direction)
u = 0 (it is dropped from rest)

Therefore, its velocity after t = 4.0 s is:

Downward, because the sign is positive.
Learn more about free fall motion:
brainly.com/question/1748290
brainly.com/question/11042118
brainly.com/question/2455974
brainly.com/question/2607086
#LearnwithBrainly
Answer:
f = 735 Hz
Explanation:
given,
Person distance from speakers
r₁ = 4.1 m r₂ = 4.8 m
Path difference
d = r₂ - r₁ = 4.8 - 4.1 = 0.7 m
For destructive interference

where, n = 1, 3,5..
we know, λ = v/f

v is the speed of the sound = 343 m/s
f is the frequency

for n = 1

f = 245 Hz
for n = 3

f = 735 Hz
Hence,the second lowest frequency of the destructive interference is 735 Hz.