2 boxes on flat ground and an incline

AI Thread Summary
The discussion focuses on analyzing the dynamics of two boxes connected by a rope, with one on a flat surface and the other on a 30-degree incline. Participants suggest starting with a free body diagram to identify forces acting on each box, including gravitational force, tension, and friction. The net force equation is discussed, with emphasis on calculating the gravitational force components along the slope and perpendicular to it. Participants express confusion about deriving equations that involve both tension and acceleration. The conversation highlights the need for a systematic approach to solve for both variables in the context of frictionless and friction-influenced scenarios.
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1. A 10 kg box on a level surface is attached by a weightless, unstretchable rope to a 7.0 kg box which rest on a 30 degree incline. Find the rate of acceleration and the tension in the rope if... a) there is no friction ... b) coefficient of friction is 0.10 for both boxes



2. F_net = m*a



3. Honestly, I'm not sure where to start
 
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Start with the box on the slope. Draw the force of gravity straight down and calculate its size in N. Draw a pair of vectors that begin and end in the same place as that first one, an arrow along the slope and another straight into the slope. Use trigonometry to figure out the size of each of these vectors. The force into the slope is canceled out (the slope pushes back equally), so it is the component along the slope that causes the two masses to accelerate. Use F = ma.
 
Do you know how to draw free body diagram? Identify the various forces acting on each body.
Find the net force acting in the downward direction. From that find the acceleration.

Edit: Hi Delphi51, we are racing.
 
Delphi51 said:
Start with the box on the slope. Draw the force of gravity straight down and calculate its size in N. Draw a pair of vectors that begin and end in the same place as that first one, an arrow along the slope and another straight into the slope. Use trigonometry to figure out the size of each of these vectors. The force into the slope is canceled out (the slope pushes back equally), so it is the component along the slope that causes the two masses to accelerate. Use F = ma.

rl.bhat said:
Do you know how to draw free body diagram? Identify the various forces acting on each body.
Find the net force acting in the downward direction. From that find the acceleration.

So is the F_net = F_gravity parallel - F_tension - F_friction? because that is what I got after drawing a free body diagram...

EDIT: and now I'm trying to solve and I'm getting an expression with two variables - tension and acceleration
 
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