Aforce of 50 newtons causes an object to accelerate at 10 meters per second squared. what is the mass of the object?

 Use F = ma, where F is force (in newtons), m is mass (in kg) and a is acceleration (in m/s²).  

In this case F = 50 N and a = 10 m/s², so we have the equation:  

50 = 10m.  

Now divide both sides by 10, getting:  

m = 5 kg.  

So the answer is C. 5.0kg

The force of the floor on the briefcase

Explanation:

The briefcase hits the floor and stops the falling which is reacting to the briefcase that was falling and hits the floor.

The falling briefcase would be the action force because it is moving downward

and

The reaction force would be the floor because it will react on the briefcase.

Hope this Helps