Science
In which of these situations is a person doing work?
A. a school crossing guard raises a stop sign that weighs 10 N
B. a student walks quickly while carrying a heavy backpack
C. a man exerts a 350 N force on a rope attached to a house
The answer is A - a school crossing guard raises a stop sign that weighs 10 N
Power has to do with which of the following?
A. how much work is done
B. Joules
C. how fast the work is done
How much work is done on a 10 N block that is lifted 5 m in the air by a pulley?
Your answer has to have the correct NUMBER and UNIT (W or J) to be considered correct.
The answer is 50 J
How much power did you use if you push a 100 N sled 4 meters in 20 seconds?
Your answer has to have the correct NUMBER and UNIT (W or J) to be considered correct.
The answer is 20 W
What is the purpose of any machine?
To make work easier
Which simple machine consists of a rope going over a grooved wheel, and changes the direction of the work?
A pulley
Which simple machine is made of two inclined planes together, and is used to force apart two parts of an object?
A wedge
Which simple machine has a bar that pivots over a fixed point?
A lever
Which simple machine is just a simple slanted surface?
An inclined plane
Which simple machine transfers a small amount of force to a very long incline plane wrapped around a cylinder?
A screw
Which simple machine is actually two or more simple machines that work together?
A compound
Which simple machine transmits work from a big circle to a smaller one?
A wheel and axle
What is a fulcrum?
A. the part of the pulley that the rope goes over
B. the part of a lever that the bar pivots over
C. the part that spirals around a screw
The answer is B - the part of a lever that the ar pivots over
What determines the class of a lever?
A. how much force the machine has
B. how close the load is to the pivot point
C. whether it changes the force or the direction
The answer is B. how close the load is to the pivot point
Which of the following is an example of a wedge?
A. bike tire
B. teeter-totter
C. axe
The answer is C - axe
Which of the following is an example of an inclined plane?
A. ramp
B. knife
C. ski lift
The answer is A - ramp
Which of the following is an example of a lever?
A. hose faucet
B. screw top lid
C. hammer
The answer is C - hammer
Which of the following is an example of a pulley?
A. head of a crane
B. bottle opener
C. front teeth
The answer is A - head of a crane
Which of the following is an example of a compound machine?
A. bowling ball
B. can opener
C. steering wheel
The answer is B - can opener
Describe how simple machines help us today
AMV