Jon Sheppard's Class Review for Tuesday March 22, 3011

Okay, so today be basically did the first 2 problems on the "Newton's Second Law Review Problems.

#1. An 80 kg water skier is being pulled by a boat with a force of 220 N causing the skier to accelerate at 1.8 meters per second per second. Find the drag force on the skier.

so the normal force and the gravitational forces are each 800 N(up and down arrows), and the force of tension of the rope on the skier is 220 N. To find the drag force, use the funbal=(a)(m)-1.8 X 80 = 144=funbal. So the drag force is 220-144=76 N.

#2. A 2000 kg car is slowed down uniformly from 20m/s to 5m/s in 4 seconds. Determine the average unbalanced force on the car during this time, and how far the car traveled while slowing down.

Well, to find the Funbal, you first have to find the acceleration, which is V=at+vo-5=a(4)+20=-3.75m/s/s. Then funbal=(a)(m)-(3.75)(2000)=-7000 N. Then the distance covered is Chang in X=1/2(at)^2 - -3.75 X 4= 15^2= 225m.

Thank you for your time and cooperation, i really appreciate it ;)

Love,

yours truly, Jon Sheppard