Answer:
t = 6 s
Explanation:
This is a free fall exercise
y = y₀ + v₀ t - ½ g t²
If the balloon is released its initial velocity is zero, when it reaches the floor its height is also zero, we substitute
0 = y₀ + 0 - ½ g t2
t = √(2yo / g)
let's calculate
t = √ (2 176.4 / 9.8)
t = 6 s
the balloon must be released 6 s before the person reaches the building
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Comentarios
Answer:
By convention a negative torque leads to clockwise rotation and a positive torque leads to counterclockwise rotation.
here weight of the child =21kgx9.8m/s2 = 205.8N
the torque exerted by the child Tc = - (1.8)(205.8) = -370.44N-m ,negative sign is inserted because this torque is clockwise and is therefore negative by convention.
torque exerted by adult Ta = 3(151) = 453N , counterclockwise torque.
net torque Tnet = -370.44+453 =82.56N , which is positive means counterclockwise rotation.
b) Ta = 2.5x151 = 377.5N-m
Tnet = -370.44+377.5 = 7.06N-m , positive ,counterclockwise rotation.
c)Ta = 2x151 = 302N-m
Tnet = -370.44+302 = -68.44N-m, negative,clockwise rotation.
Near the surface of reflection, reflected wave may interfere with incident wave leading to production of constructive and as well as destructive interference. This in turn, can result to resonance as well as enhancement of the sound intensity as the waves of reflection adds to incident wave. Therefore, the girl would higher intensity of reflected waves as compared to incident waves.
Therefore, statement A is correct.
The answer is having fewer neutrons than protons or electrons.
