Answer:
Efficiency = 30% = 0.3
Explanation:
The general formula for efficiency of a device is given as:
Efficiency = (Desired Output/ Input) * 100%
Here, in our case, we have a petrol engine as a device. So, we analyze it for the efficiency calculations. Here, we have:
Chemical Potential Energy = 1000 J
Kinetic Energy = 300 J
Heat and Sound Energy = 700 J
Now, we know that the desired output of a car or the purpose of a car is to provide Kinetic energy, while all other forms of energy such as heat and sound energies are produced as waste. And the chemical energy is provided to car as input, in form of fuel. Therefore,
Input = Chemical Potential Energy = 1000 J
Desired Output = Kinetic Energy = 300 J
Therefore,
Efficiency = (300 J/1000 J) * 100%
<u>Efficiency = 30% = 0.3</u>
The ball's maximum potential energy at point-R.
(Potential energy depends on height.)
Answer:
the answer is number 2
Explanation:
because the weight of the scale is added
Your brother would be described as a speeder.
Answer: vl = 2.75 m/s vt = 1.5 m/s
Explanation:
If we assume that no external forces act during the collision, total momentum must be conserved.
If both cars are identical and also the drivers have the same mass, we can write the following:
m (vi1 + vi2) = m (vf1 + vf2) (1)
The sum of the initial speeds must be equal to the sum of the final ones.
If we are told that kinetic energy must be conserved also, simplifying, we can write:
vi1² + vi2² = vf1² + vf2² (2)
The only condition that satisfies (1) and (2) simultaneously is the one in which both masses exchange speeds, so we can write:
vf1 = vi2 and vf2 = vi1
If we call v1 to the speed of the leading car, and v2 to the trailing one, we can finally put the following:
vf1 = 2.75 m/s vf2 = 1.5 m/s
