Sam runs 9 kilometers in 2.5 hours. what is his speed?
1 answer:
Considering the definition of speed, the speed of Sam is 3.6 .
Speed is a quantity that expresses the relationship between the space traveled by an object. That is, the speed is associated with the change of position of an object in space within a certain amount of time.
The speed can be calculated using the expression:
In this case, you know:
- displacement= 9 km
- time= 2.5 h
Replacing in the definition of speed:
Solving:
<u><em>speed= 3.6 </em></u>
Finally, the speed of Sam is 3.6 .
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Answer:
86MJ
Explanation:
THE TOPIC FROM WHICH THE QUESTION IS OBTAINED IS WORK, ENERGY AND POWER
- Power is defined as the time rate of doing work.
- Power =
- If the energy use is in joules and the time is in seconds, then power is a measure of watts. 1watt = 1 joule per second.
- According to the question, we need to find how much energy does one house use during each 24 hour day ( Already given time = 24hours) when the average rate of electric energy consumption in one house is 1.0 kW ( we have been given power = 1kW).
- Power = 1kW = 1 × 10³W
- Time = 24hours = 24 ×3600 = 86400seconds.
- It is important we have our time in seconds so as to be consistent with unit and dimension
Power =
1 × 10³W =
- Energy used =1 × 10³W × 86400
- Energy used = 86400000J = 86.4 ×
W = 86.4MJ
The question requested the answer in 2 significant figures and the answer is 86MJ