The answer is letter C. <span>A train travels from the bottom of a hill to the top of a hill, its moves slower by the time it reaches the top is an example of negative acceleration.
In physics, acceleration can be described as an objects change of velocity. When an object gains velocity, it is positive acceleration, and negative acceleration for the opposite.
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Answer:
208.33 W
141.26626 seconds
Explanation:
E = Energy = 
t = Time taken = 8 h
m = Mass = 2000 kg
g = Acceleration due to gravity = 9.81 m/s²
h = Height of platform = 1.5 m
Power is obtained when we divide energy by time
The average useful power output of the person is 208.33 W
The energy in the next part would be the potential energy
The time taken would be
The time taken to lift the load is 141.26626 seconds
Answer:
835.29 Hz
Explanation:
When moving towards the source of sound, frequency will be given by
f*=f(vd+v)/v
Where f is the freqiency of the source, vd is the driving speed, v is the speed of sound in air, f* is the inkown frequency when moving forward.
Substituting 800 Hz for f, 340 m/s for v and 15 m/s for vd then
f*=800(15+340)/340=835.29411764704 Hz
Rounded off, the frequency is approximately 835.29 Hz
