Simple Kinematics problem

In summary, a small steel ball dropped from rest takes 0.5 seconds to fall through a vertical distance of 1.25m. Using the equation v=s/t, the actual speed of the ball when it has fallen through a vertical distance of 1.25m can be determined. The formula s=vt is only valid for constant speed, but since the ball is accelerating, the correct equations to use are s=\frac{1}{2}at^2+v_0t+x_0 and v=at+v_0. Combining these equations, the speed can be calculated using the formula s = t*(u+v)/2.
  • #1

Homework Statement



A small steel ball, dropped from rest, takes 0.5s to fall through a vertical distance of 1.25m.
Determine the actual speed of the ball when it has fallen through a vertical distance of 1.25m, assuming that acceleration is constant.


Homework Equations



v=s/t

The Attempt at a Solution



Long ago I was helped by a friend to get the result
( 1.25m x 2 ) / 0.5s = 5ms-1

but I've forgotten how did he come to that conclusion, and the reason behind (1.25mx2), help is much appreciated .
 
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  • #2
The formula [itex]s=vt[/itex] is only valid for constant speed. Does an object fall with constant speed?

Your friend used the following, correct equations:

1) [itex]s=\frac{1}{2}at^2+v_0t+x_0[/itex]
2) [itex]v=at+v_0[/itex]

These are valid for constant acceleration. You will need to combine both of them to get the answer.
 
  • #3
s = t*(u+v)/2
 

What is a simple kinematics problem?

A simple kinematics problem involves calculating the motion of an object without considering the forces acting on it. It typically involves using equations such as distance, velocity, and acceleration to determine the position of an object at a given time.

What are the three basic equations of kinematics?

The three basic equations of kinematics are displacement (d = v0t + ½at^2), velocity (v = v0 + at), and acceleration (a = Δv / t). These equations relate the initial and final position, velocity, and acceleration of an object in linear motion.

How do you solve a simple kinematics problem?

To solve a simple kinematics problem, you first need to identify the known and unknown variables. Then, you can use the three basic equations of kinematics to solve for the unknown variable. It is important to pay attention to units and use the correct equation for the given scenario.

What is the difference between linear and angular kinematics?

Linear kinematics involves the motion of an object along a straight line, while angular kinematics involves the motion of an object along a circular path. The equations and principles used to solve these types of problems are different, but they both fall under the broader category of kinematics.

Why is understanding kinematics important?

Understanding kinematics is important because it allows us to describe and predict the motion of objects in our everyday lives. It is also the basis for more complex concepts in physics, such as dynamics and energy. Kinematics is essential in fields such as engineering, robotics, and sports science.

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