Question

2. A 3 kg mass is pushed against a horizontal spring of force constant 25 N/m on a frictionless table. The spring is attached to the table and the mass is not attached to the spring at all. a) how far do you have to compress the spring so that it has potential energy of 12 J? b) when you release the spring all this energy is transferred to the mass-how fast does the mass move when no longer in contact with the spring? +45 mls collides with a 1450 kn car moying to the

Answer 1

(a) Spring potential energy is given as

E = 1/2 * k * x²

where k is spring constant and x is the distance by which spring is compressed

12 = 1/2 * 25 * x²

x = 0.9797 m

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(b) when releases, all this potential energy is converted to kinetic energy

so,

1/2kx² = 1/2mv²

v = sqrt ( kx² / m)

v = sqrt ( 25 * 0.9797² / 3)

v = 2.828 m/s