If something is going down a hill it can help slow it down
it can stop you from flying off a rollercoaster
Answer:
5.88×10⁸ W
Explanation:
Power = energy / time
P = mgh / t
P = (m/t) gh
P = (1.2×10⁶ kg/s) (9.8 m/s²) (50.0 m)
P = 5.88×10⁸ W
Sorry don’t know this one
Answer:
b) 472HZ, 408HZ
Explanation:
To find the frequencies perceived when the bus approaches and the train departs, you use the Doppler's effect formula for both cases:

fo: frequency of the source = 440Hz
vs: speed of sound = 343m/s
vo: speed of the observer = 0m/s (at rest)
v: sped of the train
f: frequency perceived when the train leaves us.
f': frequency when the train is getTing closer.
Thus, by doing f and f' the subjects of the formulas and replacing the values of v, vo, vs and fo you obtain:

hence, the frequencies for before and after tha train has past are
b) 472HZ, 408HZ