Answer:
The average power the student expended to overcome gravity is 560W, Watts is a units of work it is Joules /time or kg*/
Explanation:
Weight = 700N
The power is the work in (Joules) or (N*m) in a determinate time (s) to get Watts (W) units for work
A radar receiver indicates that a pulse return as an echo in 20 μs after it was sent. The reflecting object would be 3000 m away .
Phenomenon of hearing back our own sound is called an echo. It is due to successive reflection of sound waves from the surfaces or obstacles of large size. To hear an echo, there must be a time gap of 0.1 second in original sound and the reflected sound.
Given
time = 20 μs = 20 * s
let distance to the reflecting surface be = x
total distance travelled by pulse will be = 2x
speed = 3.0 × m/s
distance = speed * time
2x = 3.0 × * 20 *
x = 3000 m
The reflecting object would be 3000 m away
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