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# Velocity time graphs

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9 off-topic
May 11, 2019

#1
+4

b)  It starts at 0 km/hr at 9:00 and smoothly accelerates until it is moving at 50 km/hr at 9:15; this means that its average speed is 25 km/hr for 1/4 hour; thus, the distance travelled is (25 km/hr ) x (1/4 hr) = 6.25 km.

From 9:15 until 9:45, it travels at the constant speed of 50 km/hr for 1/2 hr; thus, the distance travelled is (50 km/hr) x (1/2 hr) = 25 km.

At 9:45, it smoothly accelerates until its speed is 100 km/hr at 10:00. Thus, its average speed is 75 km/hr and the distance travelled is ( 75 km/hr) x (1/4 hr) = 18.75 km.

From 10:00 until10:30, it travels at the constant speed of 100 km/hr; thus, the distance travelled is (100 km/hr) x (1/2 hr) = 50 km.

From 10:30 until 11:00, it smoothly decelerates, giving an average speed of 50 km/hr for 1/2 hour and a distance of (50 km/hr) x (1/2 hr) = 25 km.

The total distance is:  6.25 km  +  25 km  + 18.75 km  +  50 km  + 25 km  =  125 km.

c)  The average speed =  (total distance ) / (total time)  =  (125 km) / (2 hr)  =  62.5 km/hr

May 11, 2019

#1
+4

b)  It starts at 0 km/hr at 9:00 and smoothly accelerates until it is moving at 50 km/hr at 9:15; this means that its average speed is 25 km/hr for 1/4 hour; thus, the distance travelled is (25 km/hr ) x (1/4 hr) = 6.25 km.

From 9:15 until 9:45, it travels at the constant speed of 50 km/hr for 1/2 hr; thus, the distance travelled is (50 km/hr) x (1/2 hr) = 25 km.

At 9:45, it smoothly accelerates until its speed is 100 km/hr at 10:00. Thus, its average speed is 75 km/hr and the distance travelled is ( 75 km/hr) x (1/4 hr) = 18.75 km.

From 10:00 until10:30, it travels at the constant speed of 100 km/hr; thus, the distance travelled is (100 km/hr) x (1/2 hr) = 50 km.

From 10:30 until 11:00, it smoothly decelerates, giving an average speed of 50 km/hr for 1/2 hour and a distance of (50 km/hr) x (1/2 hr) = 25 km.

The total distance is:  6.25 km  +  25 km  + 18.75 km  +  50 km  + 25 km  =  125 km.

c)  The average speed =  (total distance ) / (total time)  =  (125 km) / (2 hr)  =  62.5 km/hr

geno3141 May 11, 2019
#6
0

Deleted .......

Guest May 11, 2019
edited by Guest  May 11, 2019
#5
+2

Also, there are 100 squares underneath the blue line, and each square  =  5/4 km

100 * 5/4 km  =  125 km

May 11, 2019
#7
+1

One question, hectictar......as I don't know much about these kinds of graphs.....how did you determine that each square is (5/4)km    ???   CPhill  May 11, 2019
#8
+2

One unit on the time axis is  1/8  of an hour, and one unit on the velocity axis is 10 km/h.

1/8 h * 10 km/h  =  5/4 km  hectictar  May 11, 2019
#9
+1

OK...got it.....THX!!!!   CPhill  May 11, 2019