A 50.0-kg skier starting from rest travels 200 m down a hill that ...

[elizabeth18]

A 50.0-kg skier starting from rest travels 200 m down a hill that has a 20.0 slope. When the skier reaches the bottom of the hill, her speed is 30.0 m/s.
 
  (a) How much work is done by friction as the skier comes down the hill?
  (b) What is the magnitude of the friction force if the skier travels directly down the hill?

Question 2

A series LRC ac circuit has a resistance of 4.0 k, a capacitance of 33.0 F, and an inductance of 23.0 H. If the frequency of the alternating current is 2.0/ kHz,
 
  what is the phase angle between the voltage and the current?
  A) 23 rad B) -1.6 rad C) 1.5 rad D) 3.1 rad

[connor417]

Answer to Question 1

(a) -1.11  104 J
(b) 55.3 N

Answer to Question 2

C

[elizabeth18]

Wow, this really help

[hramirez205]

Gracias!