Intro to Newton’s Second Law

  1. Draw the free body diagram for the following descriptions. Label the forces in the x-direction and the forces in the y-direction
  2. An object lies motionless on flat ground.
  1. An object slides at a constant speed without friction.
  1. An object slides down a hill without friction
  1. Friction prevents an object from sliding down a hill
  1. An object is pulled upwards by a force, F, at an angle  to the flat surface.
  1. An object is pushed downwards by a force, F, at an angle  to the flat surface.
  1. A thrown ball is at the top of its parabolic path.
  1. A man pulls a 50.0 kg box at a constant speed across the floor. He applies a 200. N force at an angle of 30.0 o
  2. Draw the free body diagram
  3. Sum the forces in the x-direction. What is the value of the frictional force opposing the motion?
  1. Sum the forces in the y-direction. What is the value of the normal force?
  1. A man pushes a 2.0 kg broom at a constant speed across the floor with a force of 5.0 N at a 50.0o angle.
  2. Draw the free body diagram
  3. Sum the forces in the y-direction. What is the value of the normal force?
  1. Sum the forces in the x-direction. What is the value of the frictional force opposing the motion?
  1. If the frictional force were suddenly reduced to zero, what should happen to the broom?
  1. A 20.0 kg mass is allowed to accelerate down a frictionless 15 o ramp.
  2. Draw the free body diagram for the block
  3. Determine the value of the x-component of the force of gravity.
  1. What is the acceleration of the block down the ramp?
  1. How long will it take for the block to slide 30.0 m if it started from rest?
  1. An applied 25 N force pushes on a 5.0 kg block resting on a frictionless horizontal surface. The force is directed downwards at an angle of 20.0o
  2. Draw a free body diagram of the block.
  3. Determine the x-component of the applied force.
  1. What is the acceleration of the block?
  1. What is the normal force on the block?
  1. A 70.0 kg box is pulled by a 400. N force at an angle of 30.0o to the horizontal. The force of kinetic friction is 75.0 N. What is the acceleration of the box? Remember your free body diagram. (Hint: Friction is a force that always opposes motion)
  1. A 15.0 kg block sits on a 35.0o incline. A force of 150. N pulls the block up the ramp.
  2. Draw the free body diagram on the block.
  3. What is the x-component of the force of gravity acting on the block?
  1. What is the acceleration of the block?
  1. Assuming that now there is a frictional force acting on the block of 25.0 N. what is the new acceleration of the block?