Calculating Magnitude?

Question

A ball on a porch rolls 60 cm to the porch's edge, drops 40 cm, continues rolling on the grass, and eventually stops 80 cm from the porch's edge.

What is the magnitude of the ball's total displacement, in cm?

I have a really sh**y physics teacher, I'd appreciate if someone could work the problem out and explain each step.

Thanks

Answer 1

you have to add 3 vectors. Using the vertical as Y, they are

A = 60 cm angle = 0 deg

B = 40 cm angle = -90 deg

C = 80 cm angle = 0 deg

You can do it by getting the X and y components and adding

Ax = 60

Ay = 0

Bx = 0

By = -40

Cx = 80

Cy = 0

Rx = 140

Ry = -40

magnitude of R = √(40² + 140²) = 146 cm

.

Answer 2

You Mis-spelled sh***y.  It has three ***'s, not 2 ** as you have spelled it.

You cannot numerically solve this problem unless you know the diameter of the ball (so you can know the radius), but the answer is that it is the volume of a cylinder that is 180 cm's. long using the formula for cylindrical volume.  

V=Pi X  r (sq) X h, (h being 180 cms.)  The X's are "times".

Displacement being the volume of air through which the ball travels in its 180 cm. journey.  Magnitude meaning the size of the displaced air or space through which the ball has travelled.