A charging bull elephant with a mass of 5500 kg comes directly toward you with a speed of 4.70 m/s . You toss a 0.160-kg rubber ball at the

Question

A charging bull elephant with a mass of 5500 kg comes directly toward you with a speed of 4.70 m/s . You toss a 0.160-kg rubber ball at the elephant with a speed of 7.50 m/s(a) When the ball bounces back toward you, what is its speed? (b) How do you account for the fact that the ball’s kinetic energy has increased?

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Nho 4 years 2021-08-21T14:43:24+00:00 1 Answers 84 views 0

Answers ( )

  1. danthu
    0
    2021-08-21T14:44:26+00:00
    Reply

    Answer:

    v2 = – 16.899 m/s

    velocity of ball increases so that the kinetic energy of the ball increases.

    Explanation:

    given data

    mass of elephant, m1 = 5500 kg

    mass of ball, m2 = 0.160 kg

    initial velocity of elephant, u1 = – 4.70 m/s

    initial velocity of ball, u2 = 7.50 m/s

    solution

    we consider here final velocity of ball = v2

    so  collision formula is express as for v2

    v_{2}=\left ( \frac{2m_{1}}{m_{1}+m_{2}} \right )u_{1}+\left ( \frac{m_{2}-m_{1}}{m_{1}+m_{2}} \right )u_{2}      ……………..1

    put here value and we get

    v_{2}=\left ( \frac{2\times 5500}{5500+0.160} \right )(-4.70)+\left ( \frac{0.16-5500}{5500+0.160} \right )(7.50)  

    solve it we get

    v2 = – 16.899 m/s

    here negative sign shows that the ball bounces back towards you

    and

    here we know the velocity of ball increases so that the kinetic energy of the ball increases.

    and due to this effect, it will gain in energy is due to the energy from the elephant mass

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