Newton's 3rd Law & Friction

Quiz Review

Any last minute questions?

Multiple Choice

What is the equation for Newton's 2nd law of motion?

• $F\Delta t=\Delta p=p-po$
  

• $v=u+at$
  

• $f=ma$

• None of the Above

Multiple Choice

A constant force acts on an object of mass 5kg for a duration of 2s. It increases the object's velocity from

 $3ms^{-1}$  to  $7ms^{-1}$ . Find the magnitude of the applied force.

• 20N

• 5N

• 16N

• 10N

Open Ended

What's your good thing for today? OR what's something you look forward to this weekend?

Multiple Choice

If the person is pushing backwards with the paddle, why do they move forward?

• The person will actually move backwards, they need to paddle the other way

• The water pushes back with an equal and opposite force

• The person is pushing harder than the water

• The water pushes back with a greater force than the person

Multiple Choice

When the person pushes on the wall, and the wall pushes back, why does the person move and not the wall?

• The wall has more mass

• The person is pushing harder than the wall

• The wall is pushing harder than the person

• The skateboard is pushing on the person

Multiple Choice

A book rests on a table. The force of gravity pulls down on the book with a force of 20N. What prevents the book from falling down into the ground?

• The table and the book are pushing back with an acceleration of 9.8m/s².

• The table pushes back up on the book with a force greater than 20N

• The inertia of the book is equal to the inertia of gravity

• The table pushes back up on the book with an equal and opposite force of 20N

Multiple Choice

A girl weighs 300 N what is her mass here on Earth?

• 40.8 kg

• 41 kg

• 30.6 kg

• 300 N

Multiple Choice

A squirrel has a weight of 4.9 N. What is his Mass if he is running on the Ground?

• 4.9 kg

• 9.8 N/kg

• 0.5 kg

• 5.0 kg

Multiple Choice

Find the weight of a 5kg rock on Mercury with a gravitational pull of 3.59m/s/s.

• 5kg

• 17.95N

• 1.39N

• 0.718N

Multiple Choice

What type of friction is not moving?

• static

• sliding

• fluid

• rolling

Multiple Choice

Sam is hover boarding down they hall at a constant velocity. Assuming there is friction, which of the following must be true?

• The force applied by the board must be greater than the frictional force

• The frictional force must equal the force applied by the board

• The force applied must equal zero

• There is not enough information

Multiple Choice

A box takes 40 N to start moving when the coefficient of static friction is .54. What is the weight of the box? 

• 81 N
• 18 N
• 98 N
• 74 N

Multiple Choice

What is the coefficient of static friction for steel on steel?

• 0.57
• 0.74
• 0.42
• 0.53

Multiple Choice

A box takes 40 N to start moving when the coefficient of static friction is .54. What is the weight of the box? 

• 81 N
• 18 N
• 98 N
• 74 N

Multiple Choice

What is the coefficient of static friction if it takes 44 N of force to move a box that weighs 86 N? 

• 0.78
• 0.51
• 0.78 N
• 0.58 N

Multiple Choice

What is the force of friction between a block of ice that weighs 950 N and the ground if μ = .12?

• 65 N

• 226 N

• 175 N

• 114 N