A 4.00 x 10° kg subway train is brought to a stop from a speed of 0.500 m/s in 0.600 m by a large spring bumper at the end of its track. What is the force constant k of the spring (in N/m)? (Enter a number.) N/m

U7

When a 10.0 kg stone is placed on a spring it displaces the spring 7.1 cm.  If the spring is pushed down another 30 cm and then released, how high above the release point does the stone go (in meters)?  Use g = 10 N/kg.  Hint:  Determine k using the force and displacement information given.

A block of mass 2.9 kg is sitting on a frictionless ramp with a spring at the bottom that has a spring constant of 470 N/m (refer to the figure). The angle of the ramp with respect to the horizontal is 13°.  a) The block, starting from rest, slides down the ramp a distance 54 cm before hitting the spring. How far, in centimeters, is the spring compressed as the block comes to momentary rest?  b)  After the block comes to rest, the spring pushes the block back up the ramp. How fast, in meters per second, is the block moving right after it comes off the spring?  c) What is the change of the gravitational potential energy, in joules, between the original position of the block at the top of the ramp and the position of the block when the spring is fully compressed?