Acceleration of an object given forces

In summary, the question is about an 85 kg toboggan originally accelerating at 3.0 m/s2 on frictionless snow, hitting a bare patch of concrete with a force of friction of 180 N. The task is to find the new acceleration. By subtracting the applied force of 255 N from the force of friction, 180 N, the net force is found to be 75 N east. Using the equation F=ma, the resulting acceleration is calculated to be 0.88 m/s2. However, the answer key lists the answer as 0.94 m/s2, which could be due to a typo. It is suggested to post the original question word for word to avoid any misunderstandings
  • #1
Zack K
166
6

Homework Statement


An 85 kg tobbogan that was originally accelerating at 3.0 m/s2 on frictionless snow hits a bare patch of concrete that exerts a force of friction on the sled of 180 N, what will the new acceleration be?

Homework Equations


F=ma

The Attempt at a Solution


Ok so this was originally a 2 part question but I merged it into one. I already calculated the applied force of the tobbogan on frictionless snow which is 255 N east. Now I have to find its acceleration when it hits the concrete. So I got the Fnet by subtracting the applied force by the force of friction. 255-180= 75 N east. So now I do a=F/m. So the acceleration by my understanding should be 75/85 which is 0.88 m/s2. But the answer sheet says that it is 0.94 m/s2.
 
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  • #2
Your method and aithmetic seem correct. This may be a typo in the answer key.

In the future, please quote the question exactly as stated without making any changes. Many times we get questions from students that have misinterpreted the question.
 
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Likes Zack K
  • #3
Zack K said:
225-180= 75 N
=45N not that it helps.

I suggest you post the question word for word in case there is something you missed when you merged it into one question.
 
  • #4
CWatters asked for the original unmerged question. You seem to have just reposted your merged version.
In particular, if any of the input numbers you quote in the merged version are actually results calculated for the first part of the question, they may contain rounding errors that become significant in the second stage.
 
  • #5
CWatters said:
=45N not that it helps.

I suggest you post the question word for word in case there is something you missed when you merged it into one question.
225
haruspex said:
CWatters asked for the original unmerged question. You seem to have just reposted your merged version.
In particular, if any of the input numbers you quote in the merged version are actually results calculated for the first part of the question, they may contain rounding errors that become significant in the second stage.
Sorry I accidentally posted that and am trying to delete it. I don't know how to delete. Also the answer I got was a whole number. No rounding was required
 
  • #6
No problem. I didn't notice that 3*85 is 255 not 225.
 
  • #7
Thanks guys for the help. I'm assuming that the answer key had a typo.
 
  • #8
Zack K said:
Sorry I accidentally posted that and am trying to delete it.
You cannot. Please use the report feature if this happens and a mentor can delete the post for you as I have done.
 

Related to Acceleration of an object given forces

1. What is acceleration?

Acceleration is the rate of change of an object's velocity. It is a vector quantity, meaning it has both magnitude and direction. It is calculated by dividing the change in velocity by the change in time.

2. What are some common forces that can cause acceleration?

Some common forces that can cause acceleration include gravity, friction, and applied forces such as pushing or pulling on an object.

3. How is acceleration related to force?

According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This means that a greater force will result in a greater acceleration, while a greater mass will result in a smaller acceleration.

4. Can an object have acceleration without a force acting on it?

No, an object cannot have acceleration without a force acting on it. This is because acceleration is defined as the result of a force acting on an object. If there is no force, there will be no change in the object's velocity and therefore no acceleration.

5. How do you calculate the acceleration of an object given forces?

To calculate the acceleration of an object given forces, you can use the formula: acceleration (a) = net force (F) / mass (m). This means that to find the acceleration, you must first determine the net force acting on the object and its mass. Then, simply divide the net force by the mass to find the acceleration.

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