Is the Friction Force Determined by a Suspended Mass and Cart Movement?

[PhysicsAdvice]

1. If a cart is being pulled from rest by over 75cm in 2s by a suspended mass of 100g attached to the cart via a rope and pulley, what is the friction of the surface?



2. My question is whether the fapp force is the suspended mass. I know I need
Ff= μFN, Fn= -(fappy+Fg) and to get acceleration I'll need d=vit+0.5at^2, is this correct so far? and is the suspended mass indeed the fapp?

 

[PhanthomJay]

1. If a cart is being pulled from rest by over 75cm in 2s by a suspended mass of 100g attached to the cart via a rope and pulley, what is the friction of the surface?



2. My question is whether the fapp force is the suspended mass.

No, the suspended mass is accelerating, so the tension force applied to the cart (and acting on the suspended mass) is not the same as the weight of the suspended mass.

I know I need
Ff= μFN, Fn= -(fappy+Fg) and to get acceleration I'll need d=vit+0.5at^2, is this correct so far? and is the suspended mass indeed the fapp? [/b]

Your problem statement is missing information, such as the mass of the cart. Please present the problem as written.

 

[PhysicsAdvice]

I apologize, the mass of the cart is 75g, what would the firs step in solving this be?

if M=mass of cart and m=mass of suspended mass, could (M+m)x a + Ff= mxg work? Then solve for a since I have enough and then solve for Ff?

 

[PhanthomJay]

I apologize, the mass of the cart is 75g, what would the firs step in solving this be?

if M=mass of cart and m=mass of suspended mass, could (M+m)x a + Ff= mxg work?

Yes, it will work, but why?? You must draw free body diagrams of each mass and apply Newton's laws.

Then solve for a since I have enough and then solve for Ff?

You've got to determine the acceleration first based on the given information of displacement and time. Then solve for the friction force.

 

[rwisz]

I would first clarify the variables and units used in this scenario. The cart's displacement is given as 75cm in 2 seconds, which can be converted to 0.75m in 2 seconds. The mass of the suspended mass is given as 100g, which can be converted to 0.1kg. The friction coefficient, μ, is a dimensionless constant that depends on the surface and the objects in contact.

1. To determine the friction of the surface, we need to use the equation Ff= μFN, where Ff is the force of friction, μ is the friction coefficient, and FN is the normal force. In this scenario, the normal force is equal to the sum of the force applied by the suspended mass (fapp) and the force of gravity (Fg). Therefore, we can calculate the friction force by multiplying the coefficient of friction by the sum of the suspended mass force and the force of gravity.

2. The equation for acceleration, d=vit+0.5at^2, is correct. However, the suspended mass is not the same as the applied force (fapp). The suspended mass is the mass that is being pulled by the rope, and it exerts a force on the cart through the rope and pulley system. The applied force, or fapp, is the force that is being applied to the suspended mass, not the other way around. Therefore, the suspended mass is not the same as the applied force and cannot be used interchangeably in the equation for friction force.