Physics Mechanics Question?

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jack_flynn92

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Does anybody know how to go about doing this? Thanks

A 0.50 kg glider on an air track is pulled along frictionlessly by a tensile force arising from a hanging 11.0 N weight. Over what distance will it travel in order that 15.0 J of work be done on it?
 
The work done on the glider in this case is transformed into a change in kinetic energy because there is no change in elevation. The sum of the forces along the direction of motion must equal the mass times acceleration.

Σ F = m a

Let m(2) be the hanging mass and m(1) the mass of the glider. Then

m(2) g = [ m(1) + m(2) ] a

The hanging weight is given in newtons so you need to convert that to mass for part of this equation. (I calculate the acceleration to be 6.8 m/s²)

The work done by the tension force is just T x d, where d is the distance traveled.

T d = ½ m(1) v² = ½ m(1) [2 a d] = 15 J

Now you can calculate d. Note that you don't need to find the tension here because the product T x d is the 15 J you are given. I get an answer of 4.4 m which seems to me a pretty long track and a long way for the hanging mass to fall. You might check this. Often problems aren't set up to be realistic, but it's worth double checking.
 
The work done on the glider in this case is transformed into a change in kinetic energy because there is no change in elevation. The sum of the forces along the direction of motion must equal the mass times acceleration.

Σ F = m a

Let m(2) be the hanging mass and m(1) the mass of the glider. Then

m(2) g = [ m(1) + m(2) ] a

The hanging weight is given in newtons so you need to convert that to mass for part of this equation. (I calculate the acceleration to be 6.8 m/s²)

The work done by the tension force is just T x d, where d is the distance traveled.

T d = ½ m(1) v² = ½ m(1) [2 a d] = 15 J

Now you can calculate d. Note that you don't need to find the tension here because the product T x d is the 15 J you are given. I get an answer of 4.4 m which seems to me a pretty long track and a long way for the hanging mass to fall. You might check this. Often problems aren't set up to be realistic, but it's worth double checking.
 
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