Correct ones are
- Technical improvements that have made alternative energy sources more practical to use
- Increase in concern for environment.
why?
Fossil fuels are hydrocarbons
- Hydrocarbons on burning with oxygen releases harmful carbon dioxide .
Answer:
52.47706 mph
54.5 mph
Explanation:
The average speed is given by


Julie's average speed on the way to Grandmother's house is 52.47706 mph

Average speed on the return trip is 54.5 mph
Don't over think it!
For example, if you do 5 laps in 5 minutes then you do one lap per minute. If you use that example and you apply it to your problem you'll notice that the answer is simply C. 1km/min.
Best wishes!
Answer:
We conclude that the centripetal force needed to keep a 7kg mass moving in a circle of 4 meters radius at 15m/s is 393.75 N.
Explanation:
Given
To determine
We need to determine the centripetal force needed to keep a 7kg mass moving in a circle of 4 meters radius at 15m/s.
We know a centripetal force acts on a body to keep it moving along a curved path.
We can determine the centripetal force using the formula

where
is the mass
is the velocity
is the radius
is the centripetal force
substitute m = 7, r = 4, and v = 15 in the formula



N
Therefore, we conclude that the centripetal force needed to keep a 7kg mass moving in a circle of 4 meters radius at 15m/s is 393.75 N.
Answer:
The answer is a wedge.
Explanation:
The wedge is a combination of two inclined planes. It is used to separate bodies which are held together by large forces, e.g, splitting timber
M.A.= slant height of wedge/thickness of wedge.
Hence a long thin wedge has a higher mechanical advantage than a short thick one; or the smaller the angle theta between the slant heights, the greater the mechanical advantage.