A 2.5kg block slides along a frictionless surface with a speed of 4 m/s. The blocks slides along until it makes contact with a spring, compressing the spring 15 cm from its rest length at which point the block is momentarily at rest. (a) how much energy is stored in the spring? (b) what is the spring constant?

A block of 5 kg is pushed up against a platform that is attached to a spring of 1200 N/m. The spring is compressed 25 cm. The block starts out 5 m from point P and is released from rest. To the left of point P the surface is frictionless. To the right of point P the surface is frictional with coefficients of static and kinetic friction of 0.5 and 0.25, respectively. All parts of this problem must be solved using energy methods with the exception of cases discussed in lecture. a) Calculate the energy stored in the spring. b) What is velocity of the block once it leaves the platform? c) What is the work done by friction once the block is 2 m to the right of point P? d) How far from point P does the block stop?

Problem 2. A 4.0 kg object moving with an initial velocity of 8.0 m/s on a horizontal surface comes torest due to friction after it travels a distance of 10.0 m.(a) What is the increase of thermal energy caused by friction? Take g = 9.8 m/s2.(b)What is the coefficient of kinetic friction between the object and the surface?

25 kg bear slides, from rest, 12 m down a Lodgepole Pine tree, moving with a speed of 5.6 m/s just before hitting the ground. What change occurs in the gravitational potential energy of the bear Earth system during the slide?