Chapter 1 - Translational Motion

Question 1

An object experiences 8N south, 11N north and 4N east. What is the magnitude of resultant force?

Answer 1

Draw a triangle
A^2 + B^2 = C^2
3^2 + 4^2 = 25
*must square root the C^2
therefore C is 5

Question 2

Define instantaneous velocity

Answer 2

the slope of displacement vs time

*magnitude of velocity decreases if velocity and acceleration have opposite direction

Question 3

Define acceleration

Answer 3

Acceleration = velocity / time 
units = m/s^2

Question 4

Define equation for displacement of uniformly accelerated motion

Answer 4

X = Xo + Vot + 1/2 at^2
V = Vo + aat
V^2 = Vo^2 + 2ax

Question 5

An asteroid takes 8.1 minutes to round trip. How far away is it? Speed of light = 3 x 10^8 ms^-1

Answer 5

Distance = velocity x time
divide 8.1 / 2 to get how far away it is then multiply by 60 to get minutes
4 x 60 = 240 or 2.4 x 10^2
(2.4 x 10^2) (3 x 10^8) 
= 7.2 x 10^10

Question 6

If you travel 90m north in 15 seconds then turns and travels 40m south in 5 seconds. What is the average velocity

Answer 6

Velocity = distance / time
= 50 / 20
= 2.5 m/s

Question 7

A truck goes up a 1.2km incline accelerating from its initial velocity of 14ms- to 6ms^-2 for 5 seconds. 8 seconds after reaching top it stops uniformly. What is the ratio of acceleration:decceleration?

Answer 7

V = Vo + at (acceleration)
= 14 + (6 x 5) = 44

V = Vo + at (decceleration)
0 = 44 + (a x 8)
a = 5.5
therefore the ratio of a is 6:5