Question

An object’s motion is described by the equation d= -4 sin (pi t), d is in meters and t is in seconds. (9 pts)
a) What is the objects position after 2 seconds?

b) What is the objects maximum displacement from its resting position?

c) How much time is required for one oscillation?

d) What is the frequency?

Answer 1

a) subtitute t = 2
what will you get for d ?

Answer 2

um im not sure please explain further

Answer 3

d = -4 sin 2pi = 0 because sin 2pi = 0

Answer 4

so the object moves in a circle and after 2 seconds its back where it started from, right?

Answer 5

it would appear so

Answer 6

the object's max displacement is when sin = 1 or -1, when can that happen? when the angle is either pi or 3pi/2

Answer 7

ok so what does that mean?

Answer 8

please forgive me word problems sometimes elude me

Answer 9

so the max displacement is -4 * -1 = 4 meters

Answer 10

ok

Answer 11

that's the answer for B, right?

Answer 12

yes

Answer 13

c) 2 seconds because we found that in part A, where after 2 seconds the object was back where it started from, right?

Answer 14

yes of course

Answer 15

D) the frequency is 1 oscillation divided by the time it takes to do that oscillation, so based on A and C above the frequency = 1/2 Hertz

Answer 16

Hertz is the unit used for frequencies and its equal to 1/second

Answer 17

yes thank you so much

Answer 18

welcome :)