Force Questions

[Ron]

I have got some class VIII homework questions which I am not able to answer. Can someone please help me out with them?

 

1. Which force is responsible for raising our body hair when we try to take off a terylene or polyster shirt in dry weather condition?

 

2. An object experiences a net non-zero force. Is it possible for the object to travel with a constant speed in a straight line?

 

3. When we throw a ball upwards, what happens to its speed while it is going up? Give reasons for your answer.

 

Fill in the blanks:

 

1. To draw water from a well, we have to _______ at the rope.

 

 

Please note that all questions are from the lesson "Force & Pressure".

 

Thanks,

 

Ron

[swansont]

How about you give it a shot first, and then let people help correct any mistakes.

[TonyMcC]

Reference question 3, Why not throw a ball into the air and observe what happens?

Edited August 12, 2010 by TonyMcC

[Izzy_Bee]

I have got some class VIII homework questions which I am not able to answer. Can someone please help me out with them?

 

1. Which force is responsible for raising our body hair when we try to take off a terylene or polyster shirt in dry weather condition?

 

2. An object experiences a net non-zero force. Is it possible for the object to travel with a constant speed in a straight line?

 

3. When we throw a ball upwards, what happens to its speed while it is going up? Give reasons for your answer.

 

Fill in the blanks:

 

1. To draw water from a well, we have to _______ at the rope.

 

 

Please note that all questions are from the lesson "Force & Pressure".

 

Thanks,

 

Ron

 

 

We are not suppose to give you the answers. They seem pretty simple to me, When you trough something upwards it will slow due to, air resistance and gravity.. As it comes back down it will pick up speed it will excellerate downwards at 9.81 meters per second per second.

The fil in the gaps.. Assuming there is a bucket on the end to get the water from the well using the rope, wells are normally down, sometimes they go to a underground stream, so if you angle the bucket if there was one straight down it will hit the bottom of a bent well, and not get much water at all. . If it was a normal straight one then you would pull on the rope.. and it would hopefully be filled if the bucked had collected any water.

I think thats enough (:

Need any other help just ask.

 

Truth.

Edited August 12, 2010 by Truth

[Ron]

How about you give it a shot first, and then let people help correct any mistakes.

 

 

OK....here are my answers.....

 

1. Which force is responsible for raising our body hair when we try to take off a terylene or polyster shirt in dry weather condition?

 

Frictional force but not sure

 

2. An object experiences a net non-zero force. Is it possible for the object to travel with a constant speed in a straight line?

 

No. An object experiencing a net zero force will either be at rest or will be moving at a constant speed but an object experiencing a net non-zero force will have a changing speed. Am I correct? Assuming yes, how will an object move if the object is experiencing a net zero force?

 

Can someone please correct me my wrong answers?

 

Thanks,

 

Ron

Edited August 13, 2010 by Ron

[TonyMcC]

When a skydiver leaves the airplane he is pulled toward the earth by gravity. However his speed will soon stabilise at about 120 mph. Do you think that this has a bearing on your second answer?

[swansont]

OK....here are my answers.....

 

1. Which force is responsible for raising our body hair when we try to take off a terylene or polyster shirt in dry weather condition?

 

Frictional force but not sure

 

They're referring to the static electricity, which would be the electrostatic (or electromagnetic) force.

 

2. An object experiences a net non-zero force. Is it possible for the object to travel with a constant speed in a straight line?

 

No. An object experiencing a net zero force will either be at rest or will be moving at a constant speed but an object experiencing a net non-zero force will have a changing speed. Am I correct? Assuming yes, how will an object move if the object is experiencing a net zero force?

 

 

 

Not a changing speed, but a changing velocity — velocity is a vector and you can change direction, too. An object moving in a circle can have a constant speed, yet it must be experiencing a net force.

 

As for how something can be moving with a zero net force, look at TonyMcC's example.