A) 8m/mm
B) 6m/min
C) \[\frac{8}{3}m/\min \]
D) 2 m/min
Correct Answer: D
Solution :
Key Idea: Average speed is the ratio of displacement to time taken. Displacement from 0 to\[5s=40\text{ }m\] Displacement from 5 to\[10\text{ }s=40\text{ }m\] Displacement from 0 to\[15\text{ }s=-\text{ }20m\] Displacement from 15 to\[20\text{ }s=0\] So, net displacement \[=40+40-20+0=60m\] Total time taken\[=5+5+15+5=30\text{ }mm\] Hence, average speed \[=\frac{displacement\text{ }(m)}{time(\min )}=\frac{60}{30}=2\text{ }m/min\]You need to login to perform this action.
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