Post a New Question

Physics

posted by .

A certain freely failing object requires 1.70 s to travel the last 20.5 m before it hits the ground. From what height above the ground did it fall?

  • Physics -

    Let H be the initial height.
    Let T be the time it takes to fall the full height H.
    g/2 T^2 = 4.9 T^2 = H
    (g/2)(T-1.7)^2 = 4.9(T-1.7)^2 = H - 20.5

    Combine the equations to eliminate H, so you can solve for T. Then calculate H.

    4.9T^2 = 4.9(T-1.7)^2 + 20.5
    4.9T^2 = 4.9T^2 -16.66 T +14.161 +20.5
    16.66T = 34.66
    T = 2.08 s

    H = 4.9 T^2 = 21.2 m

  • Physics -

    Find the height from which you would have to drop a ball so that it would have a speed of 6.4 m/s just before it hits the ground.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physical

    Q: a freely falling object requires 1.50s to travel the last 30.0m before it hits the ground . From what height above the ground did it fall ?
  2. physics

    A certain freely falling object requires 1.25 s to travel the last 35.5 m before it hits the ground. From what height above the ground did it fall?
  3. physics

    A certain freely failing object requires 1.70 s to travel the last 39.0 m before it hits the ground. From what height above the ground did it fall?
  4. physics

    An object is dropped from a height H above the ground. This free-falling object requires 0.904 s to travel the last 34 m before hitting the ground. From what height H above the ground did the object fall?
  5. physics

    An object is dropped from a height H above the ground. This free-falling object requires 0.904 s to travel the last 34 m before hitting the ground. From what height H above the ground did the object fall?
  6. Physics

    A certain freely falling object requires 1.50 seconds to travel the las 30.0 meters before it hits th ground. From what height above the ground did it fall?
  7. maths

    A body of mass 11kg falls freely from rest from a height of 15m above the ground. 3m above the ground it breaks through a thin roof before continuing its fall. (a) given that the work done in breaking through the roof is 130 J. Calculate …
  8. maths

    A body of mass 11kg falls freely from rest from a height of 15m above the ground. 3m above the ground it breaks through a thin roof before continuing its fall. (a) given that the work done in breaking through the roof is 130 J. Calculate …
  9. Physics

    It takes a freely falling object 1.80 s to travel the last 32.00 m before it hits the ground. From how high of the ground did it fall?
  10. Physics

    A metal ball of mass 2kg is allowed to fall freely from rest from height of 5m. Calculate potential energy it possesses and kinetic energy before it reaches the ground. What happens to mechanical energy of the ball after it hits the …

More Similar Questions

Post a New Question