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A 6.6 g marble is fired vertically upward using a spring gun. The spring must be compressed 8.7 cm if the marble is to just reach a target 15 m above the marble's position on the compressed spring. (a) What is the change ΔUg in the gravitational potential energy of the marble-Earth system during the 15 m ascent? (b) What is the change ΔUs in the elastic potential energy of the spring during its launch of the marble? (c) What is the spring constant of the spring?

 May 15, 2014

Best Answer 

 #2
avatar+2353 
+5

Okay, so you can find the gravitational potential energy using ΔUg = mgh

where m is mass, g is gravitational force (usually threated as the constant 9.8N/kg ) and h is height

 

The marble gains all it's potential energy from the spring, therefore ΔUg = -ΔUs

 (Technically the spring transfers it's potential energy into kinetic energy after which it becomes potential energy) 

The formula for elastic potential energy is given by 

$$Pe = -\Delta Us = \frac{1}{2}kx^2$$

where k is the spring constant and x is the amount of compression

 

 

 edit: I think you can do the last one by yourself if you've finished these

 May 15, 2014
 #1
avatar+1314 
0

Just some help, so I can deduce the answer. I've no real clue tbh.

 

Also.. A block of mass m = 4.0 kg is dropped from height h = 32 cm onto a spring of spring constant k = 2460 N/m (see the figure). Find the maximum distance the spring is compressed.

 May 15, 2014
 #2
avatar+2353 
+5
Best Answer

Okay, so you can find the gravitational potential energy using ΔUg = mgh

where m is mass, g is gravitational force (usually threated as the constant 9.8N/kg ) and h is height

 

The marble gains all it's potential energy from the spring, therefore ΔUg = -ΔUs

 (Technically the spring transfers it's potential energy into kinetic energy after which it becomes potential energy) 

The formula for elastic potential energy is given by 

$$Pe = -\Delta Us = \frac{1}{2}kx^2$$

where k is the spring constant and x is the amount of compression

 

 

 edit: I think you can do the last one by yourself if you've finished these

reinout-g May 15, 2014
 #3
avatar+1314 
0

Thanks wil lget back to physics next week readying for the exam then.

 May 30, 2014

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