Bob Jones science 9 chapter work and machines
Terms
undefined, object
copy deck
- In science, work is accomplished when...
-
a force acts on an object as it moves through a distance.
14A - Formula for work...
-
w=f x d
14A - a newton-meter is also a...
-
joule (which is also kg x m2
_______
s2 )
14A - Things that make work easier that have only one or two parts...
-
simple machines
14A - Machines can do these 3 things, but never this...
-
can do: increase the amount of force, change the direction of force, and change speed of force
can't do: increase the amount of work done or energy expended 14A - a bar that turns on a point...
- lever. The point is the fulcrum. 14A
- Law of Moments...
-
w1d1 =w2d2
14A - In first class lever, where is the fulcrum?
-
between the effort on one end and the resistance on the other
14A - Force multiplying ability...
-
mechanical advantage
14A - mechanical advantage formula..
-
ratio of resisting force /applied force
or ratio of distance effort applied/distance resistance moves 14A - In a second class lever, the resistance is...
-
between the effort on one end and the fulcrum on the other.
14A - In a third class lever, the resistance is...
- on one end, the effort in the middle, and the fulcrum on the other end. 14A
- Name the class of these levers: wheelbarrow, biceps, seesaw.
-
second, third, first
14A - This modified lever overcomes the limited distance that a resistance can be moved with a lever...
-
wheel and axle
14B - A single fixed pulley doesn't give you any mechanical advantage but it does...
-
change the direction of force.
14B - A single moveable pulley gives you an advantage of...
-
2 (but the rope must be pulled twice as far as the weight rises)
14B - An arrangement of fixed and moveable pulleys...
-
block and tackle
14B - To find the mechanical advantage in a block and tackle...
-
count the number of ropes supporting the resistance.
14B - Distance principle...
- any reduction in the effort force will be paid for by an increased distance through with the force must act 14B
- Inclined planes reduce the ...
- effort to raise a load 14B
- The mechanical advantage of an inclined plane...
- length of incline/height
- Two inclined planes placed bottom to bottom...
- wedge
- An inclined plane wrapped around a cylinder...
- screw
- The distance between two adjacent threads on a screw...
- pitch. (also defined as the distance it moves inward for each turn it is given)
- A machine's actual performance (or ratio of work output to work input)...
- its efficiency
- Rate of doing work...
- Power
- Power formula...
- work/time
- Units for power...
- watts (W)