Math3(Reiny Please Help)

posted by Heaven

An object on Earth falls with an acceleration of a=9.81 m/s^2. A function exists between the height from which the object falls, the initial velocity of the object and the time the object spends in the air. h(t)= Vt + at^2 V=initial velocity. T= time. A= acceleration due to gravity.
A.) Lucy and Kim determine the height of a building by dropping a brick from its roof. The initial velocity will be 0 m/s because Lucy will simply let go of the brick. Kim times the fall of the brick to be 3.5 seconds. What is the height of the building?
B.) Determine the amount of time the brick is in the air if Lucy throws the brick downward with an initial velocity of 5 m/s. Round to the nearest hundredth of a second.

  1. Reiny

    h(t) - -9.81t^2 + 0t + h = 0 when it hits the ground
    when t = 3.5
    -9.81(3.5)^2 + h =0
    h = 120.1758 m

    b) repeat for the equation
    h(t) = -9.81t^2 -5t + 120.1725
    set that equal to 0
    and solve for t , reject any negative values of t

Respond to this Question

First Name

Your Answer

Similar Questions

  1. Science ( physics )

    A balloon is rising with a velocity of 4.9 m/sec releases an object from height of 96 m. a) How long after its release will the object reach the ground?
  2. Physics

    An object with a mass of 49 N falls out of a plane going 20.0 m/s at 300 m above the ground. 1)How do I find the time that the object is in the air?
  3. physics

    A 9.00 kg object starting from rest falls through a viscous medium and experiences a resistive force = -b , where is the velocity of the object. The object reaches one half its terminal speed in 5.54 s. (a) Determine the terminal speed. …
  4. Math

    The acceleration of an object g = -9.8 m/s^2. From the top of a building of 245 m., an object is thrown upwards at an initial velocity of 12m/s (a) What is the function for the velocity of the object?
  5. Physics

    An object is observed for a 5 second interval. During this time, the objects velocity increases from 2 m/s to a final velocity and the object travels 75 m. The acceleration of the object is constant. Given this information, which of …
  6. calculus help check and help

    if an object with mass m is dropped from rest, one model for its speed v after t seconds, taking air resistance into account is v= mg/c(1-e^(-ct/m)) where g is the acceleration due to gravity and c is a positive constant describing …
  7. physics

    Question: Object A is moving at a maximum speed of 6m/s towards Object B. At 50 m away Object B accelerates from the approaching Object A at 0.3m/s^2. Does Object A catch up to Object B and if yes when?
  8. math

    An object of mass 100g is thrown vertically upward from a point 60cm above the earths surface with an initial velocity of 150cm/sec. It rises briefly and then falls vertically to the earth, all of which time it is acted on by air resistance …
  9. application of differential equation

    An object of mass 100g is thrown vertically upward from a point 60cm above the earths surface with an initial velocity of 150cm/sec. It rises briefly and then falls vertically to the earth, all of which time it is acted on by air resistance …
  10. application of differential equation

    somebody please help me find the solution totally lost.... An object of mass 100g is thrown vertically upward from a point 60cm above the earths surface with an initial velocity of 150cm/sec. It rises briefly and then falls vertically …

More Similar Questions