Ray creates an energy transfer diagram for a hair dryer. However, the diagram contains an error that could be corrected in sever
al different ways.
Which of these changes would make the diagram error-free? Check all that apply.
1. reducing the amount of thermal energy to 475 J
2. increasing the amount of electrical energy to 825 J
3. increasing the amount of sound energy to 225 J
4. reducing the amount of kinetic energy to 50 J
5. reducing the amount of electrical energy to 675 J
Which of these changes would make the diagram error-free? Check all that apply.
1. reducing the amount of thermal energy to 475 J
2. increasing the amount of electrical energy to 825 J
3. increasing the amount of sound energy to 225 J
4. reducing the amount of kinetic energy to 50 J
5. reducing the amount of electrical energy to 675 J
2 answers:
The correct answer is 1,2,4.
Option 1
Since the hair drier does not create any energy, the sum of the input energy has to be equal to the sum of the output energy. The input energy is 750J. In this case, sound energy is 150J and the kinetic energy is 125J. When the thermal energy is 475J, the output energy is,
In this case, the diagram is error free.
Option 2
In this option, the input energy is 825J .The sum of the input energy has to be equal to the output energy. The sum of the output energy is calculated as shown below,
In this situation, the diagram is error free because energy is conserved.
option 4
The input energy into this system is 750J. When the kinetic energy is reduced to 50J, the output energy of the drier is then,
In this case, energy conservation is not violated, the input energy is equal to the output energy.
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The force of seat acting on the child is a reaction the force of child pressing down on the seat. This is the third Newton's law. The force of a child pressing down the seat and the force of the seat pushing up on the child are the same.
There two forces acting on the child. The first one is the gravitational force and the second one is centrifugal force. In this example, the force of gravity is always pulling down, but centrifugal force always acts away from the center of circular motion.
Part A
For point A we have:
In this case, the forces are aligned, centrifugal is pointing up and gravitational is pulling down.
Part B
At the point, B situation is a bit more complicated. In this case force of gravity and centrifugal force are not aligned. We have to look at y components of this forces, y-axis, in this case, is just pointing upward.
Part C
The child will stay in place at point A when centrifugal force and force of gravity are in balance:
The force of seat acting on the child is a reaction the force of child pressing down on the seat. This is the third Newton's law. The force of a child pressing down the seat and the force of the seat pushing up on the child are the same.
There two forces acting on the child. The first one is the gravitational force and the second one is centrifugal force. In this example, the force of gravity is always pulling down, but centrifugal force always acts away from the center of circular motion.
Part A
For point A we have:
In this case, the forces are aligned, centrifugal is pointing up and gravitational is pulling down.
Part B
At the point, B situation is a bit more complicated. In this case force of gravity and centrifugal force are not aligned. We have to look at y components of this forces, y-axis, in this case, is just pointing upward.
Part C
The child will stay in place at point A when centrifugal force and force of gravity are in balance:
Answer:
Time, t = 6.34 hours.
Explanation:
Velocity can be defined as the rate of change in displacement (distance) with time. Velocity is a vector quantity and as such it has both magnitude and direction.
Mathematically, velocity is given by the equation;
Therefore, making time the subject of formula;
Given the following data;
Displacement = 5200km
Average velocity = 820km/hr
Substituting into the equation, we have;
Time = 6.34 hours.
<em>Hence, it would take 6.34 hours for the airplane to reach its destination. </em>