# Physics

posted by
**Joe** on
.

Block A of mass 4.0 kg is on a horizontal, frictionless tabletop and is placed against a spring of negligible mass

and spring constant 650 N m. The other end of the spring is attached to a wall. The block is pushed toward the

wall until the spring has been compressed a distance x, as shown above. The block is released and follows the

trajectory shown, falling 0.80 m vertically and striking a target on the floor that is a horizontal distance of 1.2 m

from the edge of the table. Air resistance is negligible.

(a) Calculate the time elapsed from the instant block A leaves the table to the instant it strikes the floor.

(b) Calculate the speed of the block as it leaves the table.

(c) Calculate the distance x the spring was compressed.

Block B, also of mass 4.0 kg, is now placed at the edge of the table. The spring is again compressed a distance x,

and block A is released. As it nears the end of the table, it instantaneously collides with and sticks to block B.

The blocks follow the trajectory shown in the figure below and strike the floor at a horizontal distance d from the

edge of the table.

(d) Calculate d if x is equal to the value determined in part (c).

(e) Consider the system consisting of the spring, the blocks, and the table. How does the total mechanical energy

E2 of the system just before the blocks leave the table compare to the total mechanical energy E1 of the

system just before block A is released?

____ E2 < E1 ____ E2 = E1 ____ E2 > E1

Justify your answer.