Answer:
Kinetic energy is greatest at the lowest point of a roller coaster and least at the highest point.
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Answer: 1960 N
Explanation:
The bear is sliding down at constant velocity: this means that its acceleration is zero, so the net force is also zero, according to Newton's second law:
There are two forces acting on the bear: its weight W, pulling downward, and the frictional force Ff, pulling upward. Therefore, the net force is given by the difference between the two forces:
From the previous equation, we find that the frictional force is equal to the weight of the bear:
Answer:
The law of conservation of momentum states that, in the absence of an external force, the momentum of a system remains unchanged.
Explanation:
C. Wavelength is the length of one complete wave cycle 
Wavelength of a sine wave, λ, can be measured between any two points with the same phase, such as between crests, or troughs, or corresponding zero crossings as shown
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>
