Using Kinematic Equation w/ Constant Velocity: Solving Time of Fall

In summary, to use the Kinematic equation with constant velocity, you can set acceleration to 0. This will simplify the equation to d=v*t, where d is the distance, v is the velocity, and t is the time. In the given scenario of a parachute falling from a 30-meter-high cliff at a constant velocity of 1.5 meters per second, it will take 20 seconds for the parachute to hit the ground. The stone dropped from the same cliff will also take 20 seconds to hit the ground, as long as the velocity remains constant.
  • #1
celect
43
0
How do I use Kinematic equation with constant velocity.
I only have used with intital and final velocity.



A parachute dropped from a 30-meter-high cliff falls with a constant
velocity of 1.5 meters per second. Twenty-two seconds later a stone is
dropped from the cliff.

a. How long does it take the parachute to hit the ground?


b. How long does it take the stone to hit the ground?
I solved this using d=v_i * t + 1/2 * a *t ^2

24.5 seconds
 
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  • #2
Originally posted by celect
How do I use Kinematic equation with constant velocity.
I only have used with intital and final velocity.
You can use the exact same equation by setting a=0. It simplifies to d = v*t ... I hope that equation looks familiar!
 
  • #3
d=v*t+1/2*a*[tex]t^2[/tex]

-30m = (-1.5m/s)*t + 0.5 (0m/s)*[tex]t^2[/tex]

I come up with t=20s

Am I going in the right direction?
 
  • #4
yes, if the velocity remains contant
then a=0
 
  • #5
Originally posted by celect
Am I going in the right direction?
Perfect.
 

What are the kinematic equations used in solving for time of fall?

The kinematic equations used in solving for time of fall are:

  • Final Velocity = Initial Velocity + Acceleration * Time
  • Distance = (Initial Velocity + Final Velocity) / 2 * Time
  • Final Velocity^2 = Initial Velocity^2 + 2 * Acceleration * Distance
  • Distance = Initial Velocity * Time + 1/2 * Acceleration * Time^2
  • Time = (Final Velocity - Initial Velocity) / Acceleration

What is constant velocity in kinematics?

Constant velocity in kinematics means that the object is moving at a constant speed and in a straight line. This means that the acceleration of the object is zero, and therefore the velocity remains the same throughout the motion.

How do you solve for the time of fall using kinematic equations?

To solve for the time of fall using kinematic equations, you first need to identify the known values such as initial velocity, final velocity, and acceleration. Then, choose the appropriate kinematic equation that includes these values and solve for time.

Can the kinematic equations be used for objects with non-constant velocity?

No, the kinematic equations can only be used for objects with constant velocity. For objects with non-constant velocity, we need to use calculus and the concept of derivatives to calculate the velocity and acceleration at any given point in time.

What are some real-life applications of using kinematic equations with constant velocity?

Some real-life applications of using kinematic equations with constant velocity include calculating the time it takes for a ball to fall from a certain height, determining the speed and distance traveled by a car on a straight road, and predicting the time it takes for an airplane to reach its destination.

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