Exercise 1: Going airborne 1. When the helicopter is moving at a constant velocity, is there a net force acting on it?
No, if there was a net force acting upon the helicopter, the velocity would not be constant, it would move in the positive or negative direction. 2. The helicopter first moves up, and then you caused it to hover (or attempted to cause it to hover). Did there have to be a negative net force acting on the craft at some point for this to occur? Why?
Yes, in order to get the helicopter in the air, vertical has to be positive. To bring the helicopter to a hover, the vertical velocity has to be zero. In order to bring the velocity from positive to zero, a negative net force must act upon it. Exercise 2: What is the mass of the helicopter?
Force
Acceleration
Data point 1
2000 N
.98
Data point 2
1000 N
.49
3. Does the acceleration change with the net force? What is the mathematical relationship of acceleration and net force?
Yes, as the net force increases, the acceleration increases. Net force divided by acceleration always equals the same constant mass. 4. What is the mass of the helicopter? How did you determine it?
The mass is 2040.81 kg. This was determined by dividing the net force by the acceleration at any constant force. Exercise 3: Net force and acceleration 5. What lift force was required to save the day?
32,000 N. Exercise 4: Air resistance
Speed
Force
Data point 1
11.20 m/s
1000 N
Data point 2
9.67 m/s
750 N
Data point 3
7.87 m/s
500 N
Data point 4
5.50 m/s
250 N
6. Look at your data. How does the force of air resistance vary with the speed of the helicopter? Does the force of air resistance increase as helicopter speed increases, decrease as helicopter speed increases, stay the same, or is there no relationship at all? Use your data to justify your answer.
The air resistance decreases because the velocity more easily increases when net force is increased. 7. Using the guidelines above, is the relationship between air resistance force and helicopter speed a linear, inverse, or squared relationship? Or is there no relationship at all? Justify your answer using your data.
It is a squared relationship for the numbers increase exponentially, faster as the net force increases. Exercise 5: Flying your helicopter 8. What horizontal thrust force is required for the helicopter to have zero horizontal velocity? To be moving at a constant horizontal velocity?
In order for the horizontal velocity to be zero, the thrust force must be zero or the velocity would be positive or negatice. The thrust force would also have to be zero in order for the helicopter to be moving at a constant velocity or the velocity would either increase or decrease. Exercise 6 (optional): Save the day! 9. What is the required lift force? Given this lift force, what are the net horizontal and vertical forces?
25,500 lift force. Horizontal: 14.3 Vertical: -0.69
No, if there was a net force acting upon the helicopter, the velocity would not be constant, it would move in the positive or negative direction. 2. The helicopter first moves up, and then you caused it to hover (or attempted to cause it to hover). Did there have to be a negative net force acting on the craft at some point for this to occur? Why?
Yes, in order to get the helicopter in the air, vertical has to be positive. To bring the helicopter to a hover, the vertical velocity has to be zero. In order to bring the velocity from positive to zero, a negative net force must act upon it. Exercise 2: What is the mass of the helicopter?
Force
Acceleration
Data point 1
2000 N
.98
Data point 2
1000 N
.49
3. Does the acceleration change with the net force? What is the mathematical relationship of acceleration and net force?
Yes, as the net force increases, the acceleration increases. Net force divided by acceleration always equals the same constant mass. 4. What is the mass of the helicopter? How did you determine it?
The mass is 2040.81 kg. This was determined by dividing the net force by the acceleration at any constant force. Exercise 3: Net force and acceleration 5. What lift force was required to save the day?
32,000 N. Exercise 4: Air resistance
Speed
Force
Data point 1
11.20 m/s
1000 N
Data point 2
9.67 m/s
750 N
Data point 3
7.87 m/s
500 N
Data point 4
5.50 m/s
250 N
6. Look at your data. How does the force of air resistance vary with the speed of the helicopter? Does the force of air resistance increase as helicopter speed increases, decrease as helicopter speed increases, stay the same, or is there no relationship at all? Use your data to justify your answer.
The air resistance decreases because the velocity more easily increases when net force is increased. 7. Using the guidelines above, is the relationship between air resistance force and helicopter speed a linear, inverse, or squared relationship? Or is there no relationship at all? Justify your answer using your data.
It is a squared relationship for the numbers increase exponentially, faster as the net force increases. Exercise 5: Flying your helicopter 8. What horizontal thrust force is required for the helicopter to have zero horizontal velocity? To be moving at a constant horizontal velocity?
In order for the horizontal velocity to be zero, the thrust force must be zero or the velocity would be positive or negatice. The thrust force would also have to be zero in order for the helicopter to be moving at a constant velocity or the velocity would either increase or decrease. Exercise 6 (optional): Save the day! 9. What is the required lift force? Given this lift force, what are the net horizontal and vertical forces?
25,500 lift force. Horizontal: 14.3 Vertical: -0.69
