Find time given initial velocity, distance and acceleration.

  • #1

Homework Statement



Coyote falling down with a parachute holding an anvil at 10m/s. At 50m he drops the anvil.

A) How long does it take for the anvil to hit the ground?
B) what is the velocity of the anvil right before it hits the ground?

Homework Equations



X= Xo + V0T+1/2A(T^2)

g= 9.8 m/s^2

The Attempt at a Solution



50m = 10m/sT + 4.9m/s^2T^2

i use the quadratic equation and got t= 1.14 and -2.143

however i know this is wrong since i can not get a negative second and it seen like the "s" cancel out and you got T = a number without second.

also i know the answer is 2.33 s for (A) but want to know how to get that answer.
 

Answers and Replies

  • #2
157
0
Seems like you've done everything correctly except solving the quadratic. I get 2.333 and -4.37381 for my solutions. Or at least my calculator does...
 
  • #3
Seems like you've done everything correctly except solving the quadratic. I get 2.333 and -4.37381 for my solutions. Or at least my calculator does...
yeah i actually re did the quadratic i also got 2.33 and -4.373
 
  • #4
ok for

B) what is the velocity of the anvil right before it hits the ground?

i use V = Vo + AT and got V= 10m/s + 9.8 m/s^2(2.33s) got V =32.9 m/s

However the answer is in negative (as in -32.9 m/s) what did i do wrong to miss the negative sign?
 

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