FORCES
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
|
|
||||
|---|---|---|---|---|---|
| The force of air resistance is ALWAYS constant for any mass. T/F | TRUE
🗑
|
||||
| What changes force of air resistance? | speed, SA, shape
🗑
|
||||
| What does mass change with AR then? | changes effect of air resistance (path) but doesn't change air resistance F=ma and bowling pins
🗑
|
||||
| Why does a large mass and small mass fall at the same rate? | Larger inertia associated with larger mass means a larger force required to change its motion at the same rate
🗑
|
||||
| Universal gravitation: What do two objects experience? | Experience same gravitational force but acceleration is different
🗑
|
||||
| What is weight? | measure of gravitational force on a body
🗑
|
||||
| rotational inertia? | measure of an object's resistance to changes to its rotation
🗑
|
||||
| What is center of mass? | single point where a single force can be applied in any direction causing all points in system to accelerate equally
🗑
|
||||
| Inclined plane: When frictionless, what forces act? | gravity and normal force
🗑
|
||||
| What do machines do? | reduce amount of force needed to accomplish a task
🗑
|
||||
| What don't machines do? | reduce amount of work that needs to be done
🗑
|
||||
| Mechanical advantage equation? | weight of object to be supported / applied force needed to support object
🗑
|
||||
| What do you need to overcome when push object up inclined plane? | Overcome both parallel component of gravity and friction
🗑
|
||||
| Inclined plane: nonmoving object | parallel vector of gravity = static friction
🗑
|
||||
| Inclined plane: object going down @ constant velocity | parallel vector of gravity = kinetic friction
🗑
|
||||
| Inclined plane: object accelerating down inclined plane | parallel vector of gravity > Fk
🗑
|
||||
| Inclined plane: object begins to slip on inclined plane | parallel vector of gravity > Fs
🗑
|
||||
| What are the forces acting on a block on inclined plane? | gravity and normal force
🗑
|
||||
| centripetal acceleration | -speed never changes but object is always accelerating
-points toward center of circle
🗑
|
||||
| centripetal force | -points toward center of circle
-acceleration is ALWAYS accompanied by a force
-Fc is created by gravitational force
🗑
|
||||
| What are the ONLY 3 forces? | -gravitational, electromagnetic, contact
-these forces create and cause all other forces
🗑
|
||||
| Stuff moving in a circle? Think --> | F = mv^2 / r
🗑
|
||||
| Kepler's Laws | 1.) All orbital paths elliptical
2.) orbiting object moves faster and subject to greater force when closer to object it orbits
3.) T^2 is proportional to R^3
🗑
|
||||
| What is apparent weight often associated with? | normal force
🗑
|
||||
| Elevator accelerating up = Elevator decelerating down = | -elevator decelerating down
-elevator decelerating up
🗑
|
||||
| what forces act on uniform circular motion? | centripetal force (centripetal "a" ) directed towards center of circle
🗑
|
||||
| What forces act on nonuniform circular motion? | tangential force to change "a" and centripetal force produce resultant force and "a" NOT directed towards center of circle
🗑
|
||||
| Contact situations always have what forces? | Fn perpendicular and frictional parallel
🗑
|
||||
| Is static friction constant? | NO --> can reach a threshold point
🗑
|
||||
| Is kinetic friction constant? | Yes! once it moves it moves
🗑
|
||||
| Which is greater, u(s) or u(k) friction? | u(s)
🗑
|
||||
| Can static friction accelerate an object from rest? | YES
🗑
|
||||
| What does frictional force oppose? | -applied force
-no applied force - frictional force does all of the work
🗑
|
||||
| Why (-) in Hooke's Law? | force is opposite direction to displacement
🗑
|
||||
| translational equilibrium | constant speed (0 or nonzero) and constant direction
🗑
|
||||
| rotational equilibrium | not rotating or constant rotation
🗑
|
||||
| static equilibrium | velocity is constant 0
🗑
|
||||
| dynamic equilibrium | velocity is constant and not zero
🗑
|
||||
| What does a non-equilibrium state mean? | There is acceleration!
🗑
|
||||
| How to change angular velocity? | Apply torque
🗑
|
||||
| What are some examples of external forces? | friction, air resistance, normal, applied force
🗑
|
||||
| How does external force affect total ME? | -External forces are nonconservative forces
-change the total ME depending on whether positive or negative work
🗑
|
||||
| What are examples of internal forces? | gravity, magnetic, electrical, spring force
🗑
|
||||
| How does internal forces affect total ME? | -Internal forces are conservative forces
-do not change the total ME
-type of energy form changes
🗑
|
||||
| What is work done for external forces equal to? | change in mechanical energy
🗑
|
||||
| Is work the same as energy? | NO --> work is when a quantity of energy is moved from one system to another
🗑
|
||||
| What remains constant for conservative forces? | sum of kinetic and potential energies
🗑
|
||||
| Law of Universal Gravitation Equation | F = Gm1m2 / r^2
🗑
|
||||
| Kinetic Friction equation | Fk = uk * Fn
🗑
|
||||
| Static Friction equation | Fs = us * Fn
🗑
|
||||
| What is static friction? | friction opposing motion when a stationary object and surface are not moving
🗑
|
||||
| What is kinetic friction? | force resisting motion once stationary object and surface are moving
🗑
|
||||
| When is coeff of friction max? | when 2 surfaces are not moving
🗑
|
||||
| Once a block starts to slide, is there acceleration? | YES
🗑
|
||||
| Mutual forces exerted during collisions are equal / unequal in magnitude? | equal
🗑
|
||||
| What does friction depend on? | coefficient of friction, angle, and normal force
🗑
|
||||
| As angle increases for a box on an inclined plane, ____ decreases which causes net accelerating force acting on box. | normal force
🗑
|
||||
| As soon as equilibrium is disrupted, there is _____. | acceleration
🗑
|
||||
| What happens to the peak height when you kick an object into air with air resistance? | reaches lower peak, takes longer to reach ground than peak
🗑
|
||||
| What does backspin create and what to do to compensate? | additional flight time --> decrease launch angle
🗑
|
||||
| What does topspin create and what to do to compensate? | reduces flight time --> increase launch angle
🗑
|
||||
| Can friction cause acceleration? | YES
🗑
|
||||
| Does friction do work on an object? | YES --> drains energy
🗑
|
||||
| Considering air resistance, why does an elephant fall faster than a feather? | -elephant never reaches terminal velocity --> accelerates constantly
-feather quickly reaches terminal velocity
🗑
|
||||
| Considering no air resistance, does an elephant or feather fall faster? | fall the same
🗑
|
||||
| Does the force of AR ever change for a mass? | NO
🗑
|
||||
| What does AR take away from an object? | takes away energy
🗑
|
||||
| Why does large SA increase AR? | more collisions with air molecules
🗑
|
||||
| HIgher the velocity, higher /lower AR? | greater the AR
🗑
|
||||
| Why do larger masses experience less deceleration due to AR? | F= m*a
-force constant, mass increases, a decreases
🗑
|
||||
| In a collision, two objects hit each other with? | equal force
🗑
|
||||
| Does mass change if gravity changes between two planets? | NO --> only weight changes
🗑
|
||||
| With an elevator, is the tension of the cable line ever zero? | NO
🗑
|
||||
| Moving in from a larger circle to a smaller circle, does tangential speed increase or decrease? | decrease
🗑
|
||||
| 2 important rotational motion equations? | -a = v^2 / r (tangential speed)
-w = v/r (angular velocity)
🗑
|
||||
| Does a planet's orbit depends on the planet's mass? | NO
🗑
|
||||
| Does an orbiting object move faster or slower when orbital radius decreases? | faster
🗑
|
||||
| Higher coefficient of friction means? | greater friction
🗑
|
||||
| Can static friction accelerate object from rest? | YES
🗑
|
||||
| Why is it harder to start walking on an icy floor than a carpeted floor? | us for ice is much lower than us for carpet
🗑
|
||||
| Is acceleration on an inclined plane parallel / perpendicular to surface of plane? | PARALLEL
🗑
|
||||
| Mechanical advantage | weight of object to be supported / actual applied force to support object
🗑
|
||||
| What is the mechanical advantage of an inclined plane? | 1 / sin theta
🗑
|
||||
| How does the tension change within a rope in a pulley system? | IT DOESN'T CHANGE --> CONSTANT THROUGHOUT
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
507935299
Popular MCAT sets