MasteringPhysics 21 of 25 Conceptual Question 6.14 Suppose you push a hockey puc
ID: 1657592 • Letter: M
Question
MasteringPhysics 21 of 25 Conceptual Question 6.14 Suppose you push a hockey puck of mass m across frictionless ice for a time 1.0 s, starting from rest.giving the puck speed v after traveling distance d. You repeat the experiment with a puck of mass 2m. Part A How long will you have to push for the puck to reach the same speed v Express yor answer with the appropriate uints. Submit Give Up Part B How long will you have to push for the puck to travel the same distance d Express your answer with the appropriate units. Submit Give Up Continue >Explanation / Answer
v = at, since the puck starts from rest
the same force on the heavier mass, then the acceleration will only be half that of the the lighter mass:
F/m = a
F/(2m) = a/2
v = AT
v = (a/2)(T)
Clearly, you must push the heavier for a time 2t.
d = ½at²
d = ½(a/2)(T)²
½at² = ¼aT²
2t² = T²
T = (sqrt2)t