randomproblem wk5 qz1

course phy201

7/3 8

A ball starting from rest rolls 14 cm down an incline on which its acceleration is 25 cm/s2, then onto a second incline 47 cm long on which its acceleration is 7 cm/s2. How much time does it spend on each incline?

first incline: vf^2= 0cm/s^2+ 2 * 25cm/s^2* 14cm = 700 so vf= 26.46cm/s

t= (26.45cm/s)/ 25cm/s^2= 1.05s

second incline:vf^2= (26.45cm/s)^2 + 2 * 7cm/s^2* 47 cm= 1358cm/s so vf= 36.85

`dv= 36.85-26.46= 10.39 cm/s

t= (10.39 cm/s)/ 7cm/s^2= 1.48s

Well done.

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