Acceleration given weight and mass

[Klaxon]

So we just started a unit on motion.

 

The question is:

 

Calculate the mass of an object if it accelerated at 3.5m/s squared under the influence of a net force of 70N.

 

Is the way to work this out just m= w/g?

 

I got 20kg.

Edited March 5, 2016 by Klaxon

[studiot]

The net force causing the acceleration is

 

Force = mass x acceleration.

 

In the dynamics of motion we regard gravity as an acceleration (g), not a force, so

 

Weight is the name we give to the force that gravity exterts on a body of mass m.

 

W = mg

 

In this system, remember that kg are units of mass, not force or weight.

Force is in Newtons. (you have to convert if it is given in any other units)

 

So W is in Newtons, mass is in kg and acceleration is in metres per second²

 

Does this help?