Question

AP Physics 1 - Kinetic Energy and Work Name: Due Thursday 10/24 on itslearning 1. A student wearing frictionless roller skates on a horizontal surface is pushed by a friend with a constant force of 45 N. How far must the student be pushed, starting from rest, so that her final kinetic energy is 352 J? 2. A 2100 kg car starts from rest at the top of a driveway that is sloped at an angle of 20° with the horizontal. An average friction force of 4000 N impedes the car's motion so that the car's speed at the bottom of the driveway is 3.8 m/s. What was the length of the driveway? 3. A 75 kg bobsled is pushed along a horizontal surface by two athletes. After the bobsled is pushed a distance of 4.5 m starting from rest, its speel 0 m/s. magnitude of the net force on the

Answer 1

za Уток rest constant force F a F-45N final kinetic energy = 352 J Work done by force F = kinetic energy gamed - Fod = 352 (started from => 45 d = 352 > d= = 7.82 m (2) m= 2100 kg 0 - 20° friction force = 4000 N rest) U=O A V=3.8% Acceleration Forces aded m a = {F = mgsino- + - 2100X9.8Xsin 20 - 4000 2100 = 1,447 MSZ mosho ni to macosce v²u? = aad (u=0) a) do 2 (.33 ? 2x 1.447 = 4.99 m