A stone fell from the top of a cliff into the ocean. In the air, it had an average speed of 161616 \text{m/s}m/sstart text, m, slash, s, end

Question

A stone fell from the top of a cliff into the ocean. In the air, it had an average speed of 161616 \text{m/s}m/sstart text, m, slash, s, end text. In the water, it had an average speed of 333 \text{m/s}m/sstart text, m, slash, s, end text before hitting the seabed. The total distance from the top of the cliff to the seabed is 127127127 meters, and the stone’s entire fall took 121212 seconds.

in progress 0
Nguyệt Ánh 7 months 2021-08-20T17:43:41+00:00 1 Answers 0 views 0

Answers ( )

    0
    2021-08-20T17:45:40+00:00

    Answer:

    Air-7sec

    Water-5sec

    Explanation:

    -The average speed of the stone in air is given as 16m/s, average speed in water is 3m/s. And the total distance is 127m.

    Let speed in air be v_1 and in water v_2, and S is displacement:

    S=vt\\\\S=v_1t_1+v_2t_2\\\\127=16t_1+3t_2\\\\t_1+t_2=12s

    #Solving the simultaneous equations:

    t_1=12s-t_2\\\\127=16(12s-t_2)+3t_2\\\\127=192s-16t_2+3t_2\\\\t_2=5s\\\\t_1=12-5=7s

    Time in air is 7sec, Time in water is 5sec

Leave an answer

Browse

Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )