Tension in a Rope: Understanding Acceleration in Lifting a Bucket of Water

[izmeh]

I have the following problem

Pulling up on a rope, you lift a 4.25-kg bucket of water from a well with an acceleration of 1.80 m/s². What is the tension in the rope?

What part exactly does the acceleration play in this scenario?

 

[Doc Al]

Originally posted by izmeh
What part exactly does the acceleration play in this scenario?

The net force on an object determines its acceleration. Given the acceleration, you can find the net force. Tell us what you know about Newton's second law.

 

[izmeh]

net force = ma
a = f/m
1.80 = f/4.25
f = 7.65

 

[Doc Al]

First step: Describe all the forces acting on that bucket! Then add them up to find the net force.

Draw yourself a diagram.

 

[izmeh]

there is the force of me pull it up @ 1.80m/s²
the mass 4.25 pulling down...

 

[Doc Al]

Originally posted by izmeh
there is the force of me pull it up @ 1.80m/s²
the mass 4.25 pulling down...

There is a force pulling up, that's the tension (T) in the rope. There's also a force pulling down, the weight (not mass!) of the bucket&water. (Note: gravity pulls on the mass, that pull is the weight. You can calculate the weight by multiplying the mass by g, the acceleration due to gravity. g = 9.8 [m/s²])

The net force is (choosing up as positive):

F_net = T - mg

From Newton's second law:

F_net = ma

Now it's your turn. You know a (it's 1.8 m/s² upwards) and you know m . Find T. Give it a try.