A toy "spring gun" has a spring with a spring constant of 30,000 N/m and is depressed 4 cm. It shoots a plastic dart with a mass of 45 grams. How fast will the dart travel if there is no friction?
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well, the KE of the dart will equal the PE stored in the spring, right?
I'm not really grasping this concept well. I don't know if the KE of the dart is equal is the PE stored? Based on the formulas I don't know that is correct.
PE= 1/2kx^2
k=30,000
x=4cm
KE= 1/2mv^2
m=45g
v=0??
PE= 1/2kx^2
k=30,000
x=4cm
KE= 1/2mv^2
m=45g
v=0??
where else is the stored spring energy going?
the problem says no friction
the problem says no friction
KE = PE
1/2 mv^2 = 1/2 kx^2
Since k is in N/m, we need to use MKS units.
1/2 * 0.045 * v^2 = 1/2 * 30000 * 0.04^2
v = 32.7 m/s
1/2 mv^2 = 1/2 kx^2
Since k is in N/m, we need to use MKS units.
1/2 * 0.045 * v^2 = 1/2 * 30000 * 0.04^2
v = 32.7 m/s
ooooh for some reason I thought I needed to subtract PE and KE and it wasn't making any sense.
3 answers