# Calculate the forces of a mover pushing a crate

## Homework Statement

A mover pushes a 85kg crate along the floor at a constant speed through a displacement of 3,1m[E]. The coefficient of kinetic friction between the floor and crate is 0.22.
A) Calculate Fn and Fapp.

## The Attempt at a Solution

Fg=mg
=85kg*9.8N/kg
Fg=833N
So Fn=Fg
but how can i find Fapp

You may want to review friction;

Fn=weight since it is vertical. But frictional force is a fraction of this. Hint:There is a constant that you are not using.

make a body diagram and it will be more clear. Net force of the forces in the direction of the displacement equal the product of mass and acceleration. Solve for Fapp..

Net force= forces applied on the axis of the displacement

Net force= forces applied on the axis of the displacement

i don't know net force

arildno
Homework Helper
Gold Member
Dearly Missed
i don't know net force

Sure you do.
You know the crate moves with constant velocity.

What does that mean, in terms of net force acting upon the crate?

Sure you do.
You know the crate moves with constant velocity.

What does that mean, in terms of net force acting upon the crate?
i don't understand that

arildno
Homework Helper
Gold Member
Dearly Missed
If an object moves with constant velocity, what is its acceleration?
And how is acceleration tied together with forces?

If an object moves with constant velocity, what is its acceleration?
And how is acceleration tied together with forces?

but i need time to find acceleration

arildno
Homework Helper
Gold Member
Dearly Missed
but i need time to find acceleration

Eeeh, why?

i need help with AP Physics free response questions its the 2002 ap physics c queston

arildno
Homework Helper
Gold Member
Dearly Missed
i need help with AP Physics free response questions Then make your own thread! could someone reply if they are willing to help

$$Given$$

$$m=0.2kg$$
$$\Delta {h}_{2}=0m$$
$${v}_{2}=3.96m/s$$

$$Required$$

$${E}_{g} and {E}_{k}$$

$$Solution$$

$${E}_{g}={m}g\Delta h$$
$$={0.2kg}*9.8N/kg*0m$$
$${E}_{g}=0J$$

$${E}_{k}=(1/2)m{v}_{2}^2$$
$$=(1/2)0.2Kg(3.96m/s)^2$$
$${E}_{k}=1.56J$$

Last edited: