Basic Newtons second law plus friction

[stosw]

Homework Statement

A person pushes horizontally with a force of 220 N on a 50 kg crate to move it across a level floor. The coefficient of kinetic friction is 0.25.

(a) What is the magnitude of the frictional force?

(b) What is the magnitude of the crate's acceleration?

Homework Equations

µmg
F = ma
F = µma
F = Applied force - Frictional Force

The Attempt at a Solution

(a) What is the magnitude of the frictional force?

(0.25) * (50) * (9.8) = 122.5


(b) What is the magnitude of the crate's acceleration?

F = 220-122.5 = 97.5N

(97.5 / 50) = 1.95m/s^2

Edit: Nevermind, it was correct all along.

 

[anathema]

My apologies.

No worries, it's always good to double check your work. Your calculations for both (a) and (b) are correct. The only thing I would suggest is to label your units in your final answers, so it would be 122.5 N for the frictional force and 1.95 m/s^2 for the acceleration. Great job!

 

[tomcue]

I apologize for the mistake.
Good job on your attempt at the solution! You correctly used Newton's second law, F=ma, to determine the acceleration of the crate. However, there is a small error in your calculation for the frictional force. The correct equation to use is F = µmg, where µ is the coefficient of friction, m is the mass of the crate, and g is the acceleration due to gravity (9.8 m/s^2). Plugging in the given values, we get:

F = (0.25) * (50 kg) * (9.8 m/s^2) = 122.5 N

Therefore, the magnitude of the frictional force is 122.5 N. Keep up the good work!