An obnoxious brat assigns his 20.5-gram pet mouse Mickey the role of stunt mouse
ID: 2061072 • Letter: A
Question
An obnoxious brat assigns his 20.5-gram pet mouse Mickey the role of stunt mouse by stuffing him into a spring gun and shooting him up into the air at some angle. The gun's spring has a force constant of 61.7 N/m and is initially compressed 12.3 cm. When Mickey reaches maximum height, he has a horizontal velocity with a speed of 2.15 m/s. How high above his initial location in the gun does Mickey soar? (In case you are worried, a miniature parachute opens at this point and Mickey lands safely. The brat is slightly less obnoxious than we thought.) Take g = 9.81 m/s2.Explanation / Answer
(1) Energy from spring = 1/2 . k . x^2 = 0.5 . 88.9 . 0.149^2
(2) Energy that is still KE = 1/2 . m . v^2 = 0.5 . 0.0183 . 2.45^2
(3) The rest of the energy must be in GPE = m . g. h = 0.0183 . 9.81 . h
Take (2) from (1) and the remainder = (3)