SOLUTION: Its been a long time since I did problems like this. I know there a formula just can't remember, can you please walk me through them. Thanks A)How many seconds should elapse b

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Its been a long time since I did problems like this. I know there a formula just can't remember, can you please walk me through them. Thanks A)How many seconds should elapse b      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 30844: Its been a long time since I did problems like this. I know there a formula just can't remember, can you please walk me through them. Thanks

A)How many seconds should elapse between two consecutive mile markers if the
car's average speed is 65 mi/hr?
B)What is the car's average speed if it takes 65 s to travel between the mile markers?
Question 2: A car with an initial velocity of 3.5 m/s coasts with the engine off and the transmission in neutral. If the combined effect of air resistance and rolling friction causes a constant deceleration of 0.50 m/s2, after how long a time will the car come to a stop?
Question 3: An arrow is shot vertically upward. Three seconds later, it is at a height of 35m.
A)What was the initial speed of the arrow?
B)How long is the arrow in flight from launch to returning to the initial height? (Assume the arrow falls vertically downward.)
Answer by acerX(62) About Me  (Show Source):
You can put this solution on YOUR website!

#1
A)
65mi%2Fhr+=+1mi%2FXhrs
65X=1 divide by 65
x=1%2F65+or+0.01538+HOURS
0.01538hours+%2A+%2860mins%2Fhour%29+%2A+%2860secs%2Fmin%29+=+55.38secs+per+mile
B)
speed+=+distance%2Ftime
speed+=+1mile%2F65sec see part A.
------------
#2
acceleration+=+%28change+in+velocity%29%2Ftime
A=V%2Ft or t=V%2FA
t=3.5%2F0.5+=+7+seconds
------------
#3
A) Gravity has an acceleration of -9.8m/s
A=V%2Ft or V=At
V=-9.8%2835%29=-343m%2Fs we are looking for the magnitude of the velocity or V=343m/s
B) Im not sure what you are looking for here. What is the original height? the launch height the height at 35 seconds? etc.