Week 1 Motion in 2D and 3D 1

Question 1

how can the motion of a particle be described (in fundamental vectors)

Answer 1

can be described in terms of a position vector

Question 2

how is average velocity found

Answer 2

taking the ratio of displacement to the time duration

Question 3

define the instantaneous velocity in equation terms

Answer 3

v = dr/dt

Question 4

describe how the direction of instantaneous velocity differs with particle position

Answer 4

the direction is the same as the particle in that instant so is a tangent to the path of the particle at that instant

Question 5

how do you find the magnitude of the velocity vector

Answer 5

it is the square root of the sum of the squares of the velocity components in each direction
sqrt (vx^2 + vy^2 + vz^2)

Question 6

define acceleration in terms of velocity

Answer 6

derivative of velocity wrt time

a = dv/dt

Question 7

what happens to speed and direction when acceleration and velocity are parallel

Answer 7

speed changes

direction remains constant

Question 8

what happens to speed and direction when acceleration and velocity are perpendicular

Answer 8

speed remains constant

direction changes

Question 9

what happens to speed when acceleration and velocity are separated by an acute angle

Answer 9

speed increases

Question 10

what happens to speed when acceleration and velocity are separated by an obtuse angle

Answer 10

speed decreases

Question 11

how do we solve projectile motion problems

Answer 11

treat it as a 2D problem split into x and y components

Question 12

what can we say about acceleration for uniform circular motion (2 points)

Answer 12

acceleration is perpendicular to the direction of motion and acts toward centre of circle

Question 13

what can we say about acceleration for non uniform circular motion

Answer 13

acceleration has a radial component and a component parallel to v (tangential component)