3. In a room that is 2.44 m high, a spring (unstrained length = 0.30 m) hangs from the ceiling. A board whose length is 1.98 m is attached to the free end of the spring. The board hangs straight down, so that its 1.98-m length is perpendicular to the floor. The weight of the board (104 N) stretches the spring so that the lower end of the board just extends to, but does not touch, the floor. What is the spring constant of the spring?

A bungee jumper stands on the top of a bridge, if her bungee cord is 24.0 m long and has a spring coefficient of 283 N/m and she has a mass of 48.3 kg. How tall must this bridge be for her bungee cord to stretch all the way to the ground? Number Units

4.

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A 0.510 kg mass hung from a spring stretches it 0.220 m. II (a) (a) How much (in m) does it stretch two such identical springs if they are hung in parallel, as in (a) of the figure above? (c) How much (in m) does it stretch the two springs if they are hung in series, as in (b) of the figure above? (c) Calculate the effective force (in N/m) constant of a single replacement spring in each case. |N/m (left hand setup) |N/m (right hand setup)

1. A spring (k = 75 N/m) has an equilibrium length of 1.00 meter. The spring is compressed to a length of 0.50 m and a mass of 2.0 kg is placed at its free end on a frictionless slope which makes an angle of 41° with respect to the horizontal. The spring is then released. 0.50 m 0 = 41° (a) If the mass is not attached to the spring, how far up the slope will the mass move before coming to rest? (b) If the mass is attached to the spring, how far up the slope will the mass move before coming to rest? (c) Now the incline has a coefficient of kinetic friction uk. If the block, attached to the spring, is observed to stop as it reaches the spring's equilibrium position, what is µk?

9. A 7.9 kg object is suspended 10 m above the ground. Directly beneath it is a spring with a spring constant of 6500 N/m. Qualitatively describe what occurs to the energy of the system once the object is released? (Hint: Consider what occurs as the object falls, encounters the spring, and if it will go back up again!)

10. A 75.0-kg circus performer jumps from a height 4.90 m onto a trampoline and it stretches 0.35 m. Assume that the trampoline obeys Hooke's Law. How far will it stretch if the performer jumps from a height 8.1 m? 36 36 skpi skp