# Finding Mass Only Given Force

#### TheOGBacon

1. Homework Statement
A book exerts a force of 19.6 Newtons on the top of a desk. What is it's mass?
2. Homework Equations
M= Force/Acceleration

3. The Attempt at a Solution
I tried using the acceleration formula, but that only added more variables.

Related Introductory Physics Homework Help News on Phys.org

#### phinds

Gold Member
I tried using the acceleration formula, but that only added more variables.
Really? What is the acceleration due to gravity?

#### TheOGBacon

I meant I tried using the acceleration formula to get an expression that I could plug in for my force equation.

#### haruspex

Homework Helper
Gold Member
2018 Award
meant I tried using the acceleration formula
That's the one you quoted in post #1, right?
You have a force, you want to find the mass, so all you need is an acceleration, yes?
Presumably, the force is the weight of the book. If an object has mass m, what is its weight?

#### jbriggs444

Homework Helper
I meant I tried using the acceleration formula to get an expression that I could plug in for my force equation.
A somewhat different route to get there: When in doubt, always start with a free body diagram.

The acceleration of the book is zero. F=ma. So the net force on the book must be zero. What forces act on the book?

### Want to reply to this thread?

"Finding Mass Only Given Force"

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving