What is the acceleration of the block?

  • #1

Homework Statement


A 50.0-kg block is being pulled up a 16.0° slope by a force of 250 N that is parallel to the slope. The coefficient of kinetic friction between the block and the slope is 0.200. What is the acceleration of the block?

Homework Equations


FkkN
F=MA

The Attempt at a Solution


answer is .412 m/s2. I know the answer I just don't know the steps to solve this equation.
It is saying it is being pulled up, does that mean it has tension instead of normal force? it is not sitting on anything so it can not have a normal force right?
 

Answers and Replies

  • #2
Simon Bridge
Science Advisor
Homework Helper
17,874
1,655
answer is .412 m/s2. I know the answer I just don't know the steps to solve this equation.
You don't even have an equation to solve, and how do you know that is the right answer?
It is saying it is being pulled up, does that mean it has tension instead of normal force? it is not sitting on anything so it can not have a normal force right?
Surely the block is sittig on a slope? A tension is a force. Is the block being pulled by a rope or has someone just grabbed it and pulled it? Does it matter to the question?

Your first step is to sketch a free body diagram ... you will have course notes about this: so how many forces are on the block, and what are they?
 
  • #3
Surely the block is suittig on a slope?
Your first step is to sketch a free body diagram ... you will have course notes about this: so how many forces are on the block, and what are they?

In that case, there is a normal force. So the forces on the block are the Normal force, MG and 250cos16, 250 sin16
 
  • #4
Simon Bridge
Science Advisor
Homework Helper
17,874
1,655
Identify the forces themselves - you have a normal force to the slope, gravity, friction, and the pulling force.
GIve them names - so you have ##F_g=mg## pointing vertically down, ##N## points upwards at 90deg to the slope, ##f=\mu N## points down the slope and ##F=250##N points up the slope. F is only one force, not two like you wrote. Don't do the cosine and sine stuff untilyou decide how to orient your axes - hint: point x axis up the slope.
 

Related Threads on What is the acceleration of the block?

Replies
5
Views
2K
Replies
5
Views
3K
  • Last Post
Replies
6
Views
2K
Replies
15
Views
3K
Replies
6
Views
3K
Replies
1
Views
2K
  • Last Post
Replies
15
Views
7K
Replies
8
Views
3K
Top