Arock star plugs his guitar into a amplifier. the amplifier

An amplifier (often loosely called an "amp") is an electromagnetic or electronic component that boosts an electric current. If you wear a hearing aid, you'll know it uses a microphone to pick up sounds from the world around you and convert them into a fluctuating electric current (a signal) that constantly changes in strength. A transistor-based amplifier takes the signal (the input) and boosts it many times before feeding it into a tiny loudspeaker placed inside your ear canal so you hear a much-magnified version of the original sounds (the output).

Initial velocity,  u = 4.9 m/sfinal velocity = v m/sinitial height,  h₁ =  245 m    final height, h₂ = 0a = -9.8  m/s²time taken = t secondss = ut + 0.5at²⇒  (h₂-h₁) = ut + 0.5at²⇒  0-245 = 4.9t + 0.5×(-9.8)×t²⇒ -245 = 4.9t - 4.9t²⇒ 4.9t² -4.9t -245 =0solving it, we get   t = 7.59sv  = u +  at = 4.9 -9.8×7.59 = 4.9 - 74.38 = -69.48 m/svelocity is  69.48 m/s downward