Net force problem pretty simple

[jayced]

When on the ground, Ian's weight is measured to be 646 N. When Ian is on an elevator, his apparent weight is 711 N. What is the net force on the system (Ian and the elevator) if their combined mass is 1050 kg?

I know that Fnet is the sum of all forces. I don't have any examples of this problem so I just summed that Fnet=646N+711N+(1050kg x 9.8m/s)

Am I on the right track at all?

Should I be using another equation?

Thanx

 

[rl.bhat]

Apparent weight in an accelerating lift is given by
Wapp = n(g + or - a), where a is the acceleration do the lift.
From the given values find the acceleration of the lift. From that find the net force on the system.

 

[kerimek]

You are on the right track! The net force is indeed the sum of all forces acting on the system. In this case, the forces involved are Ian's weight (mg) and the normal force from the elevator (N). When Ian is on the ground, the normal force is equal to his weight (646 N). When he is on the elevator, the normal force increases to 711 N because the elevator is accelerating upwards.

To find the net force on the system, we can use the equation Fnet = ma, where Fnet is the net force, m is the combined mass of Ian and the elevator (1050 kg), and a is the acceleration. We can rearrange this equation to solve for a:

a = Fnet/m

Plugging in the values, we get:

a = (711 N - 646 N)/1050 kg = 0.062 m/s^2

This means that the net force on the system is 0.062 m/s^2, acting upwards. This makes sense since the elevator is accelerating upwards, so there must be a net force acting in that direction.

Keep in mind that this is a simplified problem and in reality, there may be other forces at play (such as friction or air resistance) that would affect the net force. But for this specific scenario, your approach and equation are correct.