Aball is dropped from the top of the empire state building to theground below. the height, y, of the ball above the ground (in feet)is given as a function of time, t (in seconds) by

.

(a) find the velocity of the ball at time t. what is the sign ofthe velocity? why is this to be expected?

(b) show that the acceleration of the ball is a constant. what arethe value and sign of this constant?

(c) when does the ball hit the ground, and how fast is it going atthat time? give your answer in feet per second and in miles perhour (1ft/sec=15/22mph).

A) ,

B) The aceleration is constant due to

C) t=8,81s

Step-by-step explanation:

Be y as the heigh (y) of the roof of the empire state (381m)

A)  to then v=-a.t, so ()  ; acceleration of gravity

since the acceleration is down  the falling speed is negative

B) The aceleration is constant due to

C)

1/800 is the right answer

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560