Question

1. A car is traveling at 85km/h, find the following:
A) Its speed in m/s
u = 85km/h
= 85km/h * 1000m/km/ 60s/min * 60min/m/h
= 85000/ 3600
= 23.61
ANS = 23.61m/s
B) How many meters will it travel in 8 seconds
= 23.61m/s * 8s
ANS = 188.88m
C) How long (in seconds) will it take to cover 2km
2km = 2000m
= 2000m/ 23.61s
= 84.70s
ANS = 84.70s
D) The average speed in km/h, if the time to travel 140km is 1 hour and 50 minutes.
average speed = Distance/ Time
= 140km/ 1.5hours
= 93.333km/h
ANS = 93.333km/h
Please let me know if I used the correct formula and have the right answer. Thanks.

2. A car is traveling at 95km/h. Find the following:
A) its speed in m/s
u = 95km/h
= 95km/h * 1000m/km/ 60s/min * 60min/m/h
= 95000/ 3600
= 26.38
ANS = 26.38m/s
B) How many meters will it travel in 6 seconds
= 26.38m/s * 6 s
= 158.28m
ANS = 158. 28m
C) How long it takes to cover 5km
5km = 5000m
= 5000m/ 26.38m/s
= 189.537s
= 3min 9.54s
ANS = 3minutes 9.54 seconds
D) The average speed in km/h, if the time to travel 250km is 2 hours and 40 minutes
average speed = distance/ time
= 250km/ 2hr 40min
= 250km/2.40
= 104.166km/h
ANS = 104.17km/h
Please let me know if I have used the correct formula and have the right answer. Thanks.

Answer 1

ok,ok,ok....lad listen up

lets see how ya did here...
THESE ARE THE CORRECT ANSWERS...
1a) 85 km/hr = 23.61 m/s (HINT: from km/hr to m/s just divide by 3.6)
1b) d = vt = (23.61)(8) = 188.88 m
1c) t = d/v = (2000)/(23.61) = 84.7 s
1d) v = d/t = (140)/(1.83) = 76.5 km/hr (HINT: 1 hr 50 min IS NOT 1.5 hr, rather its 1.83 hr)

2a) 95 km/hr = 26.38 m/s
2b) d = vt = (26.38)(6) = 158.28 m
2c) t = d/v = (5000)/(26.38) = 189.537 s = 3 min 9.537 s
2d) v = d/t = (250)/(2.667) = 93.73 km/hr (HINT: AGAIN, 2 hr 40 min IS NOT 2.4 hr, rather 2.667 hr)
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Overall, you did well (6/8). You just need to watch out with your conversions.
And always remember...HERP THE DERP!! (k..im done....but good luck in physics!)