Kinetics And Dynamics

Question 1

Vector split by Cos/Sin

Answer 1

X = Vcos theta

Y = Vsin theta

Question 2

Will magnitude change when vector is mult by scalar?

Answer 2

Yes, direction either parallel or anti parallel

Pos = same, Neg = opp direction

Question 3

What is the result of dot product (vector * vector)?

Answer 3

Scalar: A B Cos theta

Question 4

What is the result of cross product? Vector x Vector

Answer 4

Cross product: Result is vector

A B Sin theta > R H rule

Question 5

What is the difference in displacement vs speed?

Answer 5

Displacement: change in distance/time

Speed: change in actual distance traveled/time

Question 6

Equation for static friction:

Answer 6

0 less than equal to f(S) less than equal to u(s)N

• u: coef static friction
• N: normal force (usu m*g)

Question 7

Is a wheel rolling on the ground an example of dynamic friction? Why or why not?

Answer 7

No, because wheel is only in momentary contact with the ground and is static in that moment

Question 8

Equation of dynamic friction:

What is the difference from static friction equation

Answer 8

F(k) = u(k) N

F(k) always equal to u(k) N, thus will always be less than max value of static friction

Question 9

Linear motion equations:

Answer 9

Vf = vi + at

X = vi*t + at^2/2

Vf^2 = vi^2 + 2ax

Question 10

Projectile Motion Equations in two directions:

Answer 10

Vix = Vi*cos theta

Viy = Vi*sintheta

Question 11

What is the difference in incline plane vs projectile motion directions?

Answer 11

Fgparallel = sintheta (seems like X direction)

Fgperp = costheta (seems like Y)

Question 12

Uniform Circular Motion:

• what keeps this object on path
• what is the value of the tangential force?

Answer 12

F(c) = mv^2/r

• this is magnitude
• centripetal force is radially inward to maintain circular path
• Tangential force = 0

Question 13

What is usually 0 in a projectile motion equation? Why?

Answer 13

Vf, point of max height

• can use this value to solve for t
• make sure to multiple by 2

Question 14

What are two equations for displacement:

Answer 14

Vi*Vf / 2

D = vi*t + at^2/2

Question 15

What is acceleration equal to:

Answer 15

A = vf - vi / t

Question 16

Free Fall equation:

Answer 16

Y = 1/2gt^2
If vf^2 = vi^2 +2ad
- vf = square root (2gy)

Question 17

What is the understanding of terminal velocity?

• what is the relationship of velocity and air resistance?
• relationship mass and free fall?
• how do speed, velocity, acceleration, and g change

Answer 17

No Acceleration, but still has velocity

• directly prop
• mass does not change, more mass = more inertia to get in motion
• speed and velocity can change
• acceleration and g are constant

Question 18

Equation solving for time with height and gravity

Answer 18

T = square root (2y/g)

Question 19

What is equation for vf in terms of gravity and heaight

Answer 19

Vf = square root (2 g h)