Friction and Gravity Review (There are a total of 12 questions. As you view each slide, try to answer each question. The correct answer immediately follows each question)
#1 A force that tries to stop moving or prevent nonmoving objects from moving is called ______________.
#1 A force that tries to stop moving or prevent nonmoving objects from moving is called friction.
#2 Which shoes would create the least friction and why? Nike running shoes Tap shoes Hiking boots Vans sneakers
#2 Which shoes would create the least friction and why? Nike running shoes Tap shoes (smoothest bottom surface) Hiking boots Vans sneakers
#3 Which object would have the largest air resistance and why? A watermelon A pea A surfboard An iPod
#3 Which object would have the largest air resistance and why? A watermelon A pea A surfboard (larger surface area) An iPod
#4 Name the two types of friction represented in the picture below and where they are represented.
#4 Name two types of friction represented in the picture below and where they are represented. Static friction - person’s feet and the chariot floor fence and the sand Sliding friction - horse hooves and sand chariot/person/horses and air wheels and sand
#5 An attractive force that pulls objects towards one another is known as ______________.
#5 An attractive force that pulls objects towards one another is known as gravity.
#6 Match each example with its correct type of friction ___i. Static Friction a. Trying to get a refrigerator to move ___ii. Sliding Friction b. Skateboard wheels turning over a sidewalk c. Dragging a box across the floor d. Ice skates gliding along the ice
#6 Match the type of friction with its correct example A Static Friction a. Trying to get a refrigerator to move B, C, D Sliding Friction b. Skateboard wheels turning over a sidewalk c. Dragging a box across the floor d. Ice skates gliding along the ice
#7 Which scenario would have the largest gravitational pull and why? A B C
#7 Which scenario would have the largest gravitational pull and why? A B The objects are closer together C
#8 According to Newton’s 2nd Law, the platform diver will _____________ towards Earth because he has mass and ___________ is the net unbalanced force acting on him.
#8 According to Newton’s 2nd Law, the platform diver will accelerate towards Earth because he has a mass and gravity is the net unbalanced force acting on him.
#9 If three ice skaters are all wearing the same skates, which would create the least friction with the ice and why? A 30-kg child A 65-kg ice dancer A 100-kg hockey player
#9 If three ice skaters are all wearing the same skates, which would create the least friction with the ice and why? A 30-kg child (makes less contact with the ice) A 65-kg ice dancer A 100-kg hockey player
#10 Which free-falling object would have the greatest acceleration in a vacuum (outer space) ? A watermelon A pea A surfboard An iPod
#10 Which free-falling object would have the greatest acceleration in a vacuum? A watermelon A pea A surfboard An iPod None. All would have the same acceleration without air resistance.
#11 • What is the acceleration due to gravity here on Earth is _____ m/s2 ? • Explain what this number means.
#11 • What is the acceleration due to gravity here on Earth is 9.8 m/s2 ? • Explain what this number means. Every second, the object gains 9.8 m/s of speed. Time Speed 0s = 0 m/s 1s = 9.8 m/s 2s = 19.6 m/s 3 s = 29.4 m/s
#12 Which planet would have a larger gravitational pull and why?
#12 Which planet would have a larger gravitational pull and why? Jupiter - because it has significantly more mass