Answer the following questions carefully:

a)A 1.500 kg squirrel carrying a 0.045 kg acorn is initially sliding across frictionless ice at 7.0 m/s [S]. The squirrel then throws the acorn at 12.0 m/s [N70E]. Calculate the final velocity of the squirrel.

b)A 4.0 kg ball is dropped onto a vertically mounted spring and compress it a maximum of 0.30 m . Assuming the ball was dropped from a height of 2.0 m above the top of the spring, calculate the spring constant.