A car accelerates at a steady rate from 0 to 108km per hour in 30 seconds, travels at a constant speed for one minute, and then brakes at a constant rate to stop in 10 seconds.
i) Draw a velocity-time graph with velocity (vertical axis) in m/s and
time (horizontal axis) in seconds.
ii) Sketch a displacement-time graph for the motion.

Question

A car accelerates at a steady rate from 0 to 108km per hour in 30 seconds, travels at a constant speed for one minute, and then brakes at a constant rate to stop in 10 seconds.
i)	Draw a velocity-time graph with velocity (vertical axis) in m/s and 
	time (horizontal axis) in seconds.
ii)	Sketch a displacement-time graph for the motion.

asnaseer · Answer

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$v_1$ on the graph represents 108km/h converted to m/s:$$v_1=\frac{108*1000}{60*60}=30\text{m/s}$$
speed = distance/time, so:
distance = speed * time

which means the displacement-time graph is basically calculated by working out the area under the velocity-time graph.