# Question #04812

##### 1 Answer

#### Answer:

You lack an essential piece of information to be able to solve this problem.

#### Explanation:

This is an interesting problem, but it can't be answered because you don't know *how deep the object penetrates the surface upon impact.*

The information you have allows you to determine the *impact velocity* of the object quite easily. However, in order to determine the impact force, you need to determine the *acceleration* the object has **after** the impact.

To make the calculations easier, convert pounds to kilograms and feet to meters.

and

You don't need to calculate the time of the fall, so you can determine the *impact velocity* by using

Now, let's assume that the object penetrates the surface and stops after **10 cm**, which is equivalent to **0.1 m**. You can use the same general equation to determine the *stopping acceleration*,

This means that the impact force was

The interesting thing to notice here is that the **smaller** the penetration distance, the **bigger** the impact force.

For example, let's assume that you drop this object on another surface and that the stopping distance is now *100 times* smaller, i.e. **0.0001 m**. Both the stopping acceleration, and the impact force would be *100 times* greater.

The impact force would be