1. A car making a 110.0 mi journey travels at 49.7 mi/hr for the first 39.3 mi.

Question

1. A car making a 110.0 mi journey travels at 49.7 mi/hr for the first 39.3 mi. At what speed must it travel during the rest of the journey to have an average speed of 67.9 mi/hr?

2. A cat is being chased by a dog. Both are running in a straight line at constant speeds. The cat has a head start of 3.4 m. The dog is running with a speed of 9.3 m/s and catches the cat after 5.1 s. How fast did the cat run?

Please, show all of your work. This means show step by step how you arrived at your answer(s). Include any equations or formulas used to arrive at the answer(s). Thanks!

Explanation / Answer

1) 39.3 mi travlled by 49.7 mi/hr

Then 110-39.3 =70.7 mi will be travelled by v mi/hr(say)

Now (49.7+v)/2 =67.9 ==> v=86.1 mi/hr

2) Distance = speed x time
Distance covered by the dog = 9.3 x 5.1 = 47.43 m
The distance covered by the cat in the same 5.1 seconds is 3.4 m less because of the head start

or 47.43-3.4= 44.03 m

Now you have the distance, 44.03 and the time of 5.1 seconds.

then speed=44.03/5.1 =8.63 m/s

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.