Whats the net force of 4 newtons

If N is the number of forces acting on a body, the net force formula is given by,

FNet = F1 + F2 + F3….+ FN

Where,

F1, F2, F3…FN is the force acting on a body.

Net force when a body is at rest:Net force when a body is at rest

When the body is at rest, the net force formula is given by,

FNet = Fa + Fg.

Where,

Fa = applied force,

Fg = gravitational force.

Net force when a body is in motion:

Net force when a body is in motion

When a force is applied to the body, not only is the applied force acting, there are many other forces like gravitational force Fg, frictional force Ff and the normal force that balances the other force.

Therefore, the net force formula is given by,

FNet = Fa + Fg + Ff + FN.

Where,

Fa is applied force,

Fg is the gravitational force,

Ff is the frictional force,

FN is a normal force.

you get 2.3=1.21*\frac{a}2 or 4.6=1.21a or a=3.802 (b)

explanation:

the doppler effect is used by weather forecasters to measure 

moving clouds