course

A ball starting from rest rolls 11 cm down an incline on which its acceleration is 27 cm/s2, then onto a second incline 44 cm long on which its acceleration is 9 cm/s2. How much time does it spend on each incline?

A.

Vo=0

A= 27cm/s^2

X=11cm

Vf=17.23

T=.638s

V^2=Vo^2+2ax

V^2=0+2(27cm/s^2)(11cm)

V^2=297Cm/s^2

Take the square root

Vf= 17.23cm/s

V=Vo+at

17.23cm/s=0+(27cm/s^2)T

Divide by 27

T=.638s

B.

Vo=17.23cm/s

X=44cm

A=9cm/s^2

Vf=32.99cm/s

T=1.75s

V^2=Vo^2+2ax

V^2=(17.23cm/s)^2 + 2(9cms^2)(44cm)

V^2=296.8729cm^2/s^2+792cm/s

Take the square root

Vf=32.99cm/s

V=Vo+at

32.99cm/s=17.23cm/s+9cm/s^2T

Subtract 17.23cm/s from both sides

15.76cm/s=9cm/s^2T

Divide by 9

T=1.75s

The ball spends .638 seconds on the first incline and 1.75 seconds on the second incline, this is a total of 2.388 seconds on both ramps together.

Good solution.

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