hi,(adsbygoogle = window.adsbygoogle || []).push({});

i am preparing for an exam and i am really clueless about this one.

an image is attached.

The left side of the figure shows a light (`massless') spring of length 0.260 m in its relaxed position. It is compressed to 78.0 percent of its relaxed length, and a mass M= 0.150 kg is placed on top and released from rest (shown on the right).

The mass then travels vertically and it takes 1.30 s for the mass to reach the top of its trajectory. Calculate the spring constant, in N/m. (Use g=9.81 m/s2). Assume that the time required for the spring to reach its full extension is negligible.

energy conservation cannot work here because i don't have enough info.

thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Spring constant

**Physics Forums | Science Articles, Homework Help, Discussion**