Unit 2 Test: Dynamics

Question 1

Newton

Answer 1

N, Kgm/s^2

Question 2

weight (fg)

Answer 2

Fg=mg
-always goes down in FBD

Question 3

normal force

Answer 3

perpendicular to the surface
-makes sure objects do not fall through surface
-only occurs in surfaces

Question 4

newton’s first law

Answer 4

if forces are balanced, there will be no acceleration (no change in speed or direction)
-an object will continue at a constant velocity unless a net force acts on the object

Question 5

newton’s second law

Answer 5

if forces are unbalanced, there will be acceleration
-acceleration and net force directly related
-acceleration and mass inversely related
a=F(net)/m

Question 6

equillibrium

Answer 6

when an object is not accelerating, moving at a constant speed

Question 7

kinetic friction equation

Answer 7

f=MN

Question 8

static friction equation

Answer 8

f≤f(max)=MN

Question 9

what happens to normal force as you increase angle of a surface?

Answer 9

as the angle increases, normal force decreases

Question 10

what happens to friction as you decrease normal force?

Answer 10

as normal force decreases, friction will decrease and slide

Question 11

friction and applied force relationship

Answer 11

as friction grows, applied force grows

Question 12

newton’s third law

Answer 12

if object A asserts a force on B, object B asserts a force on A
-F(A on B)= F(B on A)

Question 13

Force pairs 4 requirements

Answer 13

1. forces exerted are equal in magnitude
   2.the forces are opposite in direction
   3.forces are acting on different objects
   4.same type of force

Question 14

assuming no other forces are present, what is normal force’s relationship with weight of that object?

Answer 14

normal force and weight are equal

Question 15

net force equation

Answer 15

F(net)=ma

Question 16

could an object with a net force of 0 be moving?

Answer 16

yes, with constant velocity

Question 17

projectile motion

Answer 17

-an object that is launched with some initial velocity
-follows a path entirely determined by g
-a form of free fall, accelerates only in the y direction

Question 18

vertical (projectile motion)

Answer 18

a maximum height object reaches, changes direction in y

Question 19

When finding Velocity projectile motion:

Answer 19

Vx=Vi(cos (ø)
vy=Vi(sin(ø)
Vi=initial velocity

Question 20

projectile motion y-velocity

Answer 20

changes (b/c there is acceleration)

Question 21

projectile motion x-velocity

Answer 21

constant (no acceleration)

Question 22

spring force

Answer 22

Fs=k(displacement)
k=larger k, stiffer stretch
displacement: how much you stretch a string