A 20kg mass approaches a spring at a speed of 30 m/s. The mass compresses the spring 12cm before coming to a stop. Calculate the spring constant k of the spring (N/m). A. 150 kN/m B. 41.7 kN/m C. 125 N/m D. 1.25 MN/m

625000 N / m

Explanation:

m = 20 kg

v = 30 m/s

x = 12 cm

k = ?

Here when the mass when hits at spring its speed is

Vi = 30 m/s

Finally it comes to rest after compressing for 12 cm

i-e Vf = 0 m/s

Distance = S = 12 cm = 0.12 m

using

2aS = Vf2 - Vi2

==> 2a * 0.12 = o - 30 * 30

==> a = 900 : 0.24 = 3750 m/sec2

Now we know;

F = ma

F = - Kx

==> ma = - kx

==> 20 * 3750 = - K * 0.12

==> k = 625000 N / m