How Much Force Does a 40kg Crate Exert on a 30kg Crate?

[fcb]

Homework Statement

A warehouse worker applies a force of 420 N to push two crates across the floor. One crate is 30kg and the other is 40kg. The boxes are touching each other.

The friction forces opposing the motion of the crates is a constant 2.0N for each kilogram..

Edit: The question is; Calculate the force exerted by the 40kg crate on the 30 kg crate

Homework Equations

F=ma

The Attempt at a Solution

Just substituted the answers in correctly taking into consideration the friction of 2.0N and got 240N but the answer at the end of the book saids 280N

I am not sure where i went wrong.

Could someone please help me out.

 

[thebigstar25]

is it 70kg or 40kg?

 

[fcb]

is it 70kg or 40kg?

Sorry, It was 30kg and 40kg

 

[phyzmatix]

Draw a force diagram (it doesn't have to be very complicated) with the force exerted by the warehouse worker on the boxes in one direction and the total force of the resistive friction in the other (as these are opposing forces). Since the two boxes are touching each other, you can view them as a single entity.

What is the total friction for the system? How can you use this, in light of your diagram, to calculate the force of box 'a' on box 'b'?

 

[rdl]

As a scientist, it is important to approach problems like this with precision and attention to detail. It seems that you have correctly used the equation F=ma to calculate the force exerted by the 40kg crate on the 30kg crate, taking into account the friction forces. However, it is always a good idea to double check your calculations and make sure you have correctly accounted for all the variables.

One possible explanation for the discrepancy in your answer and the one in the book could be rounding errors. Make sure you are using the exact values for mass and friction force, rather than rounded values. Another possibility is that the book is using a different method or equation to solve the problem. As a scientist, it is important to be open to different approaches and methods, and to always double check your work to ensure accuracy.

In conclusion, it seems that your approach to solving this problem was correct, but there may have been a small error in your calculations or a difference in methods used. As a scientist, it is important to always double check your work and be open to different solutions.