Question

1. Which statement about friction is true?(1 point) A. Static friction and kinetic friction in a system always act in the same direction as each other and in the opposite direction of the applied force. B. Static friction and kinetic friction in a system always act in the same direction as each other and in the same direction as the applied force. C. Static friction and kinetic friction in a system always act in opposite directions of each other and in the same direction as the applied force. D. Static friction and kinetic friction in a system always act in opposite directions of each other and in the opposite direction of the applied force. 2. A brick is resting on a smooth wooden board that is at a 30° angle. What is one way to overcome the static friction that is holding the brick in place?(1 point) A. roughen up the texture of the wooden board B. press down on the brick in a direction that is perpendicular to the board C. lower the board so it's level with the ground D. raise the board to a higher angle

Answer 1

Answer:

true 1Ay 2D

Explanation:

1) In this exercise you are asked to investigate which statements are true

A) True. The friction force opposes the movement caused by the external force,

B) False. Mantuano in the opposite direction force

C) False. The static and scientific friction force act in the same direction, since the second appears when the movement does not start and the static friction decreases.

D) Fale the static and kinetic friction forces act in the same direction

2) How to overcome friction on a ramp

A) False. If the texture of the surface becomes rough, the friction force increases

B) False. Pressing the brick against the surface increases the normal and as the friction is proportional to the normal, it also increases

C) False. By lowering the table the weight component in the friction direction decreases

D) True. When lifting the board, the weight component increases and therefore can become greater than the friction

          Wx-fr = ma

           W sin tea - my mg cos tea = m a

As it increases, the sine increases and the cosine decreases.