You have selected the correct answer and blobbed over it with your pencil.
I assume you must have looked at Saturn's average distance, found 1427,
divided that number by 6, got 237 and change, then looked at the others,
and found that 228 was the only one that's anywhere close.
Answer:
1. B
2. A
Explanation:
1. The displacement is the change in position. At t = 0, x = 1.0. At t = 8.0, x = 6.0. So from t=0 to t=8, Δx = 6.0 − 1.0 = 5.0.
2. The instantaneous velocity is the slope of the tangent line at any point of a position vs. time graph.
The average velocity is the displacement divided by the time interval.
KE = 1/2mv^2
1/2(10.5)(9)^2
1/2(10.5)(81) = 425.25 J
The frictional force is in the opposite direction
Answer:
78 km/h
Explanation:
If I normally drive a 12 hour trip at an average speed of 100 km/h, my destination has a total distance of:
- 100 km/h · 12 h = 1,200 km
Today, I drive the first 2/3 of the distance at 116 km/h. Let's first calculate what 2/3 of the normal distance is.
I've driven 800 km already. I need to drive 400 km more to reach my final destination. I need to figure out my average speed during this last 1/3 of the distance.
To do this, I first need to calculate how much time I spent driving 116 km/h for the past 800 km.
- 116 km/1 h = 800 km/? h
- 800 = 116 · ?
- ? = 800/116
- ? = 6.89655172
I spent 6.89655172 hours driving during the first 2/3 of the distance.
Now, I need to subtract this value from 12 hours to find the remaining time I have left.
- 12 h - 6.89655172 h = 5.10344828 h
Using this remaining time and my remaining distance, I can calculate my average speed.
- ? km/1 hr = 400 km/5.10344828 h
- 5.10344828 · ? = 400
- ? = 400/5.10344828
- ? = 78.3783783148
My average speed during the last third of the distance is around 78 km/h.
