1. A car traveling _ km/h is _ m behind a truck traveling _ km/h. How long will it take the car to reach the truck?
2. If you are driving _ km/h along a straight road and you look to the side for _1.0 s, how far do you travel during this inattentive period?
I need help with these problems... i didnt put the numbers cuss i need to learn to do it myself and i dont want 2 just cheat on it.
2. If you are driving _ km/h along a straight road and you look to the side for _1.0 s, how far do you travel during this inattentive period?
I need help with these problems... i didnt put the numbers cuss i need to learn to do it myself and i dont want 2 just cheat on it.
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I've made up some figures. One key point is to get units matching. E.g if distances are in metres and times are in seconds, make sure speed is in m/s.
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1. A car traveling 72 km/h is 200m behind a truck traveling 45km/h. How long will it take the car to reach the truck?
72km/h = 72,000m/h = 72,000/(60x60) m/s = 20m/s
45km/h.= 45,000m/h = 45,000/(60x60) m/s = 12.5m/s
Method 1 (If you know about relative velocity)
Velocity of truck relative tp car = 20-12.5 = 7.5m/s
Time = distance/speed = 200/7.5 = 26.7s
Method 2.
If they are level after time t, the distance travelled by the truck is d and the distance travelled by the car is d+200.
For car: distance =speed x time: d+200 = 20 x t. So d = 20t-200
For truck: distance =speed x time: d = 12.5 x t.
Solving the equations:
12.5t = 20t-200
7.5t = 200
t = 26.7s
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2. If you are driving at 50 km/h along a straight road and you look to the side for 5.0 s, how far do you travel during this inattentive period?
This is just the distance you travel at 50km/h for 5s
50km/h = 50,000m/h = 50,000/(60x60) m/s = 13.8...m/s
Distance travelled = speed x time = 13.9 x 5 = 69.4m
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1. A car traveling 72 km/h is 200m behind a truck traveling 45km/h. How long will it take the car to reach the truck?
72km/h = 72,000m/h = 72,000/(60x60) m/s = 20m/s
45km/h.= 45,000m/h = 45,000/(60x60) m/s = 12.5m/s
Method 1 (If you know about relative velocity)
Velocity of truck relative tp car = 20-12.5 = 7.5m/s
Time = distance/speed = 200/7.5 = 26.7s
Method 2.
If they are level after time t, the distance travelled by the truck is d and the distance travelled by the car is d+200.
For car: distance =speed x time: d+200 = 20 x t. So d = 20t-200
For truck: distance =speed x time: d = 12.5 x t.
Solving the equations:
12.5t = 20t-200
7.5t = 200
t = 26.7s
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2. If you are driving at 50 km/h along a straight road and you look to the side for 5.0 s, how far do you travel during this inattentive period?
This is just the distance you travel at 50km/h for 5s
50km/h = 50,000m/h = 50,000/(60x60) m/s = 13.8...m/s
Distance travelled = speed x time = 13.9 x 5 = 69.4m