A ballon, carrying a small uniform ball, starts from rest from a point on the ground at time 1 = 0 and moves vertically upwards with uniform acceleration, where f<g. At time t = T, the ball gets gently detached from the balloon and moves under gravity, Sketch the velocity - time graph for the upward motion of the ball, from t = 0 until the ball reaches its maximum height. Find the
maximum height reached by the ball in terms of T, f and g.
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The figure is missing but we can answer anyway.the correct answer is "releasing the string". in fact, when the person is holding the bow and the arrow, the kinetic energy of the arrow is still zero (because the arrow is not moving). the moment the arrow is released, it acquires a velocity v, so its kinetic energy will become different from zero: where m is the mass of the arrow and v its velocity.  all the other options, instead, do not increase the kinetic energy of the system: -  pulling farther back on the string : this will just increase the elastic potential energy of the system-  holding the arrow higher: this will increase the gravitational potential energy of the system (which is given by u=mgh, where h is the height above the ground)-  decreasing the mass of the arrow: this will decrease the gravitational potential energy of the system (which is given by u=mgh, where m is the mass)

Sound wavelength of visible light waves

Answer: - you don't have to pull very much to lift the mass