Finding the distance an object will travel

[baseballer10p]

Hi. I have a question about finding the distance an object will travel along a horizontal surface. If I have a force striking an object directly in the horizontal direction, how would I go about finding how far it will travel? I already have found the frictional force acting on the object being struck, I have the mass of the object being struck, and the force striking the object. Just for clarification, this object will be sliding across a surface, not rolling. Also, there will not be, (or shouldn't be, hopefully) any movement in the vertical direction. If anyone can help me with this, it would be greatly appreciated.

 

[Shooting Star]

A force striking an object doesn’t mean anything. A force can act on an object for a certain period of time, due to which the momentum or velocity of the body is changed.

If the frictional force is constant, then force/mass will give the deceleration. Then just apply the formula for const accn, if you know the initial speed. The final speed is zero.

 

[pixel01]

It's simple if consider the friction coeficient constant. The initial velocity is known (you've got to calculate it somehow), you can calculate the dynamic energy of the object: E =0.5mv^2. Then the distance is derived from the work done by friction force:
E = A = F*s.

 

[baseballer10p]

Shooting star, if I use the formula for constant acceleration, then I will end up with this:
(V^2-V_0^2)/(2*a) = \Delta x
If I use this equation with no acceleration, then I won't be able to get a distance because you can't divide by zero. Or, is the acceleration not zero?

 

[Shooting Star]

That's right. If the body comes to rest, then V=0, so you can find delta_x if you know the initial velo. (Remember, 'a' is -ve.)

 

[baseballer10p]

what is "e" in the equation a = -ve?

Oh, also, I only know the force striking the object, I don't know the initial velocity.

 

[Shooting Star]

"-ve" is short for negative.

As I have said earlier, "a force striking an object" is meaningless. You must know the duration for which it acted on the body, or some other information.

 

[baseballer10p]

Ok, the force acted on the body for an instant; it struck the object, and the object started moving. It was similar to a hockey stick hitting a puck.

 

[Shooting Star]

Then you have to give some info about what the impact did to the body -- chnage in momentum, energy, whatever...

 

[t-money]

Are you sure this isn't an impulse momentum problem, from there you can find the constant acceleration.

 

[baseballer10p]

It's not really a problem, I'm doing an experiment where I hit an object with a hammer to see how far it travels. I have to determine whether the mass of the object affects how far it travels. Clearly it does, but I need some kind of relationship to prove it.

 

[t-money]

F=ma-u, (F+u)/m equals net acelleration=a. now what is needed is the time the object travels when coming to a complete stop.