Kinematics of 2-D Ball Rolling Off Table

In summary, the conversation discusses a problem involving a ball rolling off a table and striking the floor. The questions ask for the time the ball was in the air and its speed when it left the table. The solution involves using the quadratic equation and kinematic equations, with the final answer being 0.4403 seconds. The individual also realizes a mistake in how they initially set up the quadratic equation.
  • #1
jedjj
26
0
2-D kinematics[solved]

Homework Statement


A ball rolls horizontally off the edge of a tabletop that is 1.90 m high. It strikes the floor at a point 1.57 m horizontally away from the table edge. (Neglect air resistance.)

(a) How long was the ball in the air?

(b) What was its speed at the instant it left the table?


2. The attempt at a solution

I have been trying to get the answer to part a for a little while now. I have been trying to use the quadratic equation to find time knowing that [tex]0=(-\Delta y)+V_{0y}*t+(g)t^2[/tex]
I have not used quadratic equation in about 4 years. Am I setting this problem up correctly when I do

[tex]t=\frac{V_{0y}+\sqrt{V_{0y}^2-(4)(-\Delta y)(g)}}{2*(g)}[/tex]
which should give me
[tex]t=\frac{{0}+\sqrt{0^2-(4)(-1.9)(g)}}{2*(g)}[/tex]
[tex]t=\frac{\sqrt{-(4)(-1.9)(g)}}{2*(g)}[/tex]

which comes to be
[tex]t=\frac{8.63}{19.6}[/tex]
[tex]t=0.4403[/tex]
I am not coming up with the correct answer according to what it is online[edit:still]. What am I doing wrong? Thanks for all the help.

[edit] I just went ahead and used kinematic equations and found the answer, but I'm still confused why the quadratic equation didn't work.
 
Last edited:
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  • #2
To start I just realized that quadratic equation is not set up properly. I will edit the equation and set it up in the way that I believe is proper.
 
  • #3
Am I giving too much information, or not enough. or is no one seeing a mistake I am making?
 

What is the concept of kinematics in relation to a 2-D ball rolling off a table?

Kinematics is the branch of physics that studies the motion of objects without considering the forces that cause the motion. In the case of a 2-D ball rolling off a table, kinematics focuses on the position, velocity, and acceleration of the ball as it moves along a two-dimensional plane.

What factors affect the motion of a 2-D ball rolling off a table?

The motion of a 2-D ball rolling off a table is affected by several factors, including the initial velocity and direction of the ball, the angle of the table, the force of gravity, and any friction or air resistance present.

How can we calculate the distance traveled by a 2-D ball rolling off a table?

The distance traveled by a 2-D ball rolling off a table can be calculated using the equation d = vt, where d is the distance, v is the initial velocity, and t is the time the ball has been in motion.

What is the difference between linear and angular velocity in the context of a 2-D ball rolling off a table?

Linear velocity refers to the speed of an object in a straight line, while angular velocity refers to the speed of an object as it rotates around a fixed point. In the case of a 2-D ball rolling off a table, linear velocity would be used to describe the speed of the ball as it moves along the table's surface, while angular velocity would be used to describe the speed of the ball as it rotates around its own axis.

How does the height of the table affect the motion of a 2-D ball rolling off it?

The height of the table does not significantly affect the motion of a 2-D ball rolling off it, as long as the angle of the table remains constant. The distance the ball travels horizontally will be the same regardless of the table's height, but the time it takes to reach the ground may vary slightly due to the ball's initial vertical velocity.

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