Finding displacement using V vs t graphs Notes

Breaking a water balloon - 2000 frames/second

V. Finding displacement using V vs t graphs

since V = d/t

then d = Vt

Area under the plot

= displacement (distance)

Ex) What is the displacement this object covered from t = 0 to t = 6 seconds?

d = Area of the triangle:

= 1/2bh

= 1/2(6 sec)(70m/sec)

= 210 m

Ex 1)

Object's displacement from
t = 1 sec to t = 3 sec?

d = Area = base x height

= (2 sec)(10 m/sec) = 20 m

Ex 2) Object's displacement from t = 6 sec to t = 8 sec ?

d = area of trapezoid

= 1/2 (h₁ + h₂) x base

d =	(25 m/s + 10 m/s)	(2 sec)
	2

= 35 m

Smallest displacement?

| Larger |
St. Mary's Physics

Largest B, Smallest D

AP Question - Find 2 times where the displacement of the object zero ?

After 4 seconds:

1/2(3 sec)-10 m/s + 1/2(1 sec)10 m/s

-15 m + 5 m

= -10 m

Answer: 5 seconds

AP Question

An object has an
acceleration of
-12 m/s²

Is it accelerating or decelerating?

Depends ....

If velocity is negative, accelerating

-100 m/s to -124 m/s in 2 sec

If velocity is positive, decelerating

124 m/s to 100 m/s in 2 sec

Acceleration

V +, A+

V-, A-

Deceleration

V+, A-

V-, A+