- #1

dustpal

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## Homework Statement

The ball launcher in a pinball machine has a spring that has a force constant of 1.20 N/cm. The surface on which the ball moves is inclined 10.0° with respect to the horizontal. If the spring is initially compressed 4.50 cm, find the launching speed of a 80 g ball when the plunger is released. Friction and the mass of the plunger are negligible.

## Homework Equations

Fs = -kx

Ws = change in KE

KE = 0.5mv^2

w = mg

## The Attempt at a Solution

w(x)=mg*sin(10) >>>>>> w(x)=0.136 N

Fs = -(1.2)(-4.50) >>>>> Fs = 5.4 N

F(netx)= Fs - w(x) >>>> 5.4 - 0.136 >>>>> F(netx) = 5.264 N

Ws = Fd >>>> Ws = 5.264*0.0450 >>>>> Ws = 0.23688 J

Ws = 0.5mv^2 >>>>> 0.23688 = 0.5(0.08)V^2 >>>>> v = 2.43 m/s (which is about twice as much as it should be)

## Homework Statement

A light spring with spring constant k1 is hung from an elevated support. From its lower end a second light spring is hung which has spring constant k2. An object of mass m is hung at rest from the lower end of the second spring.

(a) Find the total extension distance of the pair of springs. (Use k1 for k1, k2 for k2, and m and g as appropriate in your equation.) (b) Find the effective spring constant of the pair of springs as a system. We describe these springs as in series. (Use k1 for k1 and k2 for k2 as appropriate in your equation.)

## Homework Equations

Fs = -kx

w = mg

Ws =Fd = change in KE

KE = 0.5mv^2

## The Attempt at a Solution

Honestly, we didn't really cover springs all too well in our physics class so i have no clue where to even begin, just a hint would help me so much. The one example we did was on a horizontal plane so that's why i think I'm having difficulties doing vertical and inclined springs.