8.5 - Motion graphs

Question 1

define displacement

Answer 1

distance in a given direction

Question 2

displacement-time graph

• of a ball is thrown upwards and caught after falling back down
• describe and explain the shape of the graph

Answer 2

• initial large positive m = high velocity from the thrower
• ball sizes, velocity decreases = m decreases (due to deceleration of g)
• max height is reached when m=o, thus v=0
• as the ball descends, v becomes increasingly negative, thus m becomes increasingly negative (due to acceleration due to g)

Question 3

distance-time graph

• of a ball is thrown upwards and caught after falling back down
• compare the graph to the displacement-time one

Answer 3

• same graph shape as s-t for the first half, until the ball reaches its max vertical height
• afterwards, the distance continues to increase to a slowly curving up the curve. since m = speed and the distance cannot be -ve

Question 4

define velocity

Answer 4

speed in a given direction

Question 5

for a v-t graph

1- what does m =

2- what does the area under the graph =

Answer 5

1- acceleration

2-displacement

Question 6

v-t graph of a ball thrown up and caught

• what does the point where the graph intercepts the t-axies represent

Answer 6

the maximum hight, (v=0)

s = u/g

Question 7

v-t graph of a bouncing ball, intaly dropped

(down = +, up = -)

• what happens to the peak velocities and the area under the graph the more bounces the ball does

Answer 7

• peak velocities and the area under the graph (displacement) decreases

Question 8

What type of data logger can be used during motion practices to produce a s-t / v-t graph

• how does it work

Answer 8

ultrasound position detector

• automatically records the distance of an object from the sensor several times a second. attache to a computer with graph drawing software tp produce the graphs

Question 9

what are the 3 main advantages of dataloggers over traditional method

Answer 9

• more accurate data (removes human reaction times)
• higher sample rate
• data displayed in real time