(a) What is the acceleration of the bolt relative to the train car? (they also want the angle to the south from the vertical)

(b) What is the acceleration of the bolt relative to the Earth?

So the book does not explain relative acceleration properly so I just did -9.8-2.55 = -12.35 for a) which I got wrong and for b) I said its -9.8 which was also wrong

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Here is a question which I got right as it was a yes or no and I had more than 1 submission in webassign,

(a) Can a particle moving with instantaneous speed 6.00 m/s on a path with radius of curvature 2.00 m have an acceleration of magnitude 29.00 m/s2?

(b) Can it have an acceleration of magnitude 17.00 m/s2?

At first I answered both no because I got the acceleration a=v^2/r 18m/s^2 and isnt the centripetal acceleration constant? the correct answers are yes and no , I don't understand though

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In a local bar, a customer slides an empty beer mug down the counter for a refill. The height of the counter is 1.38 m. The mug slides off the counter and strikes the floor 0.20 m from the base of the counter.

(a) With what velocity did the mug leave the counter?

0.376867

(b) What was the direction of the mug's velocity just before it hit the floor?° (below the horizontal)

274.140

So in webassign I got a) correct but b) wrong although I'm pretty sure its right , I do understand the question the Vxi is the answer in a) and the Vyi is -5.200769 and I got theta =-85.85537 they want below the horizontal so I just added 360 to it, Do they want a different angle? please help