Calculating Work Done by Forces on a Moving Object

AI Thread Summary
To calculate the work done by forces on a moving shopping cart, the problem involves a 16.0 kg cart pushed at a constant velocity for 22.0 m at a 29-degree angle below the horizontal, with a 48.0 N frictional force opposing the motion. The key point is that constant velocity indicates the net force is zero, meaning the pushing force must equal the frictional force. The work done by the pushing force, frictional force, and gravitational force can be calculated using the equations W=(Fcosθ)d and W=Fd. The discussion highlights confusion regarding the relationship between the forces and the implications of constant velocity. Understanding these concepts is crucial for accurately determining the forces and work involved.
alex7298
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Homework Statement



A oerson pushes a 16.0kg shopping cart at a constant velocity for 22.0m at an angle of 29 degrees below the horizontal. A 48.0N frictional force opposes the motion of the cart.
a)what is the magnitude of the force the shopper exerts on the cart.
Determine the work done by b) the pushing force, c) the fricitonal force, and d) the gravitational force

Homework Equations



W=(Fcostheta)d
W=Fd


The Attempt at a Solution


well I am not sure where to start because using the equation W=(Fcostheta)d leaves you with two variables.
any help would be appreciated
 
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Well, what does that constant velocity tell you about total force?
 
F=ma
so the net force would be zero, which doesn't make sense becuase the cart is going forward, so wouldn't there have to be a force greater than the one that opposes it?
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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