Friction SBQ

What type of friction is not moving?

• static
• sliding
• fluid
• rolling

Which of the following is an example of friction that is helpful?

• Brakes used on a bike
• Tires from a car on the road
• Tread on the bottom of your shoes
• All are examples that are helpful

Which of the following is an example of friction that is harmful?

• Pencil marking on paper
• Engine parts wearing out
• sand placed on ice in the winter
• Using an eraser to erase marks

How would the absence of friction affect a marble traveling on a long, straight path?

• The marble’s speed would decrease.
• The marble’s speed would increase.
• The marble would stop immediately. 
• The marble would remain at constant speed.

Tags

NGSS.HS-PS2-1

When two surfaces rub, the irregularities of one surface get caught on those of the other surface?

• True
• False

What are 2 factors that determine the amount of friction between 2 objects?

• Normal force and roughness between surfaces

• hills and valleys and how smooth or rough the surface is

• Amount of force and amount of surface the comes in contact

• The force and the weight exerted on the surfaces

A block with a mass m = 5.0 kg slides down a ramp inclined at an angle Ɵ = 30° as shown below. The block accelerates at a rate of 2.0 m/s².

Find the component of the block’s weight along the ramp.

Find the frictional force between the block and the ramp

Calculate the coefficient of kinetic friction.

• Fg_x = 25N

  F_f = 15N

  μ = 0.35

• Fg_x = 43N

  F_f = 33N

  μ = 0.35

• Fg_x = 43N

  F_f = 33N

  μ = 0.77

• Fg_x = 25N

  F_f = 15N

  μ = 0.77

Tags

NGSS.HS-PS2-1

A block with mass 2 kg is on a ramp inclined at 30° to the horizontal. A 5.0 N force of friction, F_f acts on the

block as it is pulled up the ramp at constant velocity with force F, which is parallel to the ramp, as shown in the diagram below.

Find the components of the block’s weight, both parallel to the incline and Perpendicular to the incline.

What is the magnitude of force F?

Sin 30 = 0.50

Cos 30 = 0.87

• Fg_x = 10 N

  Fg_y = 17.3 N

  F = 15.0 N

• Fg_x = 17.3

  Fg_y = 10.0 N

  F = 15.0 N

• Fg_x = 17.3

  Fg_y = 10.0 N

  F = 22.3 N

• Fg_x = 10 N

  Fg_y = 17.3 N

  F = 22.3 N

Tags

NGSS.HS-PS2-1

Two blocks, weighing 250N and 350N, respectively, are connected by a string that passes over a massless pulley as shown. The acceleration and tension in the string is:

• a = 1.7 m/s²

  T = 210N

• a = 1.7 m/s²

  T = 290N

• a = 4.5 m/s²

  T = 290 N

• a = 4.5 m/s²

  T = 210 N

Tags

NGSS.HS-PS2-1

A 15 kg mass is sliding along a frictionless floor with an acceleration of 5 m/s². What is the magnitude of the net force acting on the mass?

• 15N

• 10N

• 20N

• 75N

Tags

NGSS.HS-PS2-1