tension or compression!

A 350 kg couch is suspended from two chains that form 60 degree angles with a horizontal ceiling. Howmuch weight does each chain support?

An ideal spring obeys Hooke’s law: F = −ikx.A mass of m = 0.8 kg hung vertically fromthis spring stretches the spring 0.13 m.The acceleration of gravity is 9.8 m/s2. Calculate the value of the force constant k. Answer in units of N/m.

w25 A student weights 700 N is in elevator at rest:(a) How much would a student weight if the elevator accelerates upward at 2m/s2 as in fig(a).(b) How much would a student weight if the elevator accelerates downward at .2m/s2 as in fig(b)

A light spring having a force constant of 125N/m is used to pull a 7.20kg sled on a horizontal ice rink. The coefficient of kinetic friction between the sled and the ice is 0.200. The sled has an acceleration of 1.80m/s^2.  By how much does the spring stretch if it pulls on the sled horizontallly?   If the string stretches by the same amount but is pulling the sled at 30 degrees above the horizontal, what is the new acceleration?

3. The force F required to move a box by pulling on an attached rope that forms an angle w with the horizontal is given by fmg F(w) = cOSw + f sin w where f, m, g > 0 are all constant. (a) Show that the angle wo that minimizes the required force to set the box in motion is given by arctan(f) (b) Show that this minimal force F(wo) is proportional to (a constant multiple of)

2 3 40° M I B = 39.9°and M = 1.6 kg, what is the tension in string 1?

A 74.1-kg crate is suspended between the floor and the ceiling using two spring scales, one attached to the ceiling and one to the floor. If the lower scale reads 120 N, what is the reading of the upper scale? Ignore the weights of the scales.