17.a. Explain the fundamental forces of nature. b. A SONAR (sound navigation and ranging) used ultrasonic waves to detect and locate objects

underwater. In a submarine equipped with a SONAR, the time delay between the generation of a probe wave

and the reception of its echo after reflection from an enemy submarine is found to be 77.0 s. What is the

distance of the enemy submarine? (Speed of sound in water = 1450 m s-1)

( urgently need this answer)​

Iknow the first part it is the average star i am not 100% sure

Attach the free body diagram and i will you answer the question.! : d

Distance covered, s = 8ft - 4ft = 4 ftinitial velocity, u = 34 ft/sthe acrobat is moving upwards and therefore, a = -g = -9.81 m/s^2 = 32.19 ft/s^2applying equation of motion; s = ut -1/2gt^2then,4 = 34t -1/2*32.19t^24 = 34t - 16.095t^2rearranging; -16.095t^2 + 34t - 4 = 0solving the quadratic equation; t = {-34 +/- sqrt [34^2 - 4(-16.)]}/2(-16.095) = 1.06 +/- 0.93 = 0.13 or 1.99the acrobat will take 0.13 seconds to be at 8 ft above the ground. additionally, once at the maximum height, the acrobat will move down and be at the same spot (that is height) after 1.99 seconds moving down.

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