Question

A ball at rest falls from a platform above the ground. The ball falls freely and hits the ground 1.1s later. What is the height of the platform?

Answer 1

Answer:

The height of the platform is 5.929 meters

Explanation:

- Free fall means that an object is falling freely with no forces acting on

 it except gravity

- The height of the object is the distance from the point which the

 object falls from it to the ground

The steps to solve the problem

1. Determine the acceleration of gravity

2. Decide whether the object has an initial velocity or not

3. Determine how long the object is falling

4. Calculate the height that the object falls from it

⇒ The gravitational acceleration g = 9.8 m/s²

The ball at rest falls from a platform above the ground

⇒ Initial velocity u = 0

The ball falls freely and hits the ground 1.1 s later

⇒ The time t = 1.1 s

We need to find the height (h) of the platform

The equation of the motion is h = u t + 1/2 g t²

⇒ h = u t + 1/2 g t²

⇒ u = 0 , t = 1.1 s , g = 9.8 m/s²

Substitute these values in the equation above

⇒ h = 0 + 1/2(9.8)(1.1)²

⇒ h = 5.929

The height of the platform is 5.929 meters