Question About A Simple Formula

[getfirefox]

Homework Statement

Since velocity = distance / time, the units of velocity are metres / seconds or ms^-1. Use the equations (below) to show that the unit of work done can be written as kg.m².s^-2.

acceleration = change in velocity / time
force = mass X acceleration
work done = force X distance

Homework Equations

None needed.

The Attempt at a Solution

Can anyone please explain to me what this question is asking me to do and how I might go about showing this?

Thanks guys for your help.

 

[LowlyPion]

Homework Statement

Homework Equations

None needed.

The Attempt at a Solution

Can anyone please explain to me what this question is asking me to do and how I might go about showing this?

Thanks guys for your help.

It's only a question about the "kind" of units.

Just show through substitution how the units for expressing work are
Mass*distance*distance over time*time

 

[baba89]

Sure, I would be happy to explain this question to you. The question is asking you to show that the unit of work done, which is joules (J), can be written as a combination of the base units of kilograms (kg), meters (m), and seconds (s). This can be done by using the equations provided.

First, we know that acceleration is equal to the change in velocity divided by time. In terms of units, this can be written as m/s^2 (meters per second squared).

Next, we know that force is equal to mass multiplied by acceleration. In terms of units, this can be written as kg*m/s^2 (kilograms times meters per second squared).

Finally, we know that work done is equal to force multiplied by distance. In terms of units, this can be written as kg*m/s^2 * m (kilograms times meters per second squared times meters). Simplifying this, we get kg*m^2/s^2 (kilograms times meters squared per second squared).

This is the same as the unit for work done, which is joules (J), so we have shown that the unit of work done can be written as kg.m2.s-2. This is a simple way to show the relationship between the units of velocity and work done. I hope this helps!