Hover condition (thrust = weight) in Drone Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Calculate thrust for hover

Given the drone's weight and thrust per motor, what is the total thrust when all motors run at full power?

Drone Programming

motors = 4
thrust_per_motor = 2.5  # Newtons
weight = 10  # Newtons
total_thrust = motors * thrust_per_motor
print(total_thrust)

A 10.0

B 2.5

C 40.0

D 4.0

💡 Hint

Multiply the thrust per motor by the number of motors.

Total thrust is the sum of thrust from all motors. 4 motors * 2.5 N each = 10 N total thrust.

❓ Predict Output

intermediate

Check if drone can hover

What is the output of this code that checks if the drone can hover given thrust and weight?

Drone Programming

weight = 15
thrust = 14
can_hover = thrust >= weight
print(can_hover)

A True

B False

C None

D Error

💡 Hint

Hover requires thrust to be at least equal to weight.

Since thrust (14) is less than weight (15), the drone cannot hover, so output is False.

🔧 Debug

advanced

Identify error in thrust calculation

What error does this code raise when calculating total thrust?

Drone Programming

motors = 4
thrust_per_motor = 3.0
# Missing multiplication operator
total_thrust = motors thrust_per_motor
print(total_thrust)

A SyntaxError

B TypeError

C NameError

D No error

💡 Hint

Check the line where total_thrust is assigned.

The code misses the '*' operator between 'motors' and 'thrust_per_motor', causing a SyntaxError.

🚀 Application

advanced

Adjust thrust to maintain hover with payload

If a drone weighs 12 N and carries a 3 N payload, what thrust is needed to hover?

A 3 N

B 9 N

C 12 N

D 15 N

💡 Hint

Hover thrust equals total weight (drone + payload).

Total weight is 12 N + 3 N = 15 N, so thrust must be at least 15 N to hover.

🧠 Conceptual

expert

Effect of thrust imbalance on hover stability

What happens if one motor produces less thrust than others during hover?

A The drone hovers perfectly without change

B The drone gains altitude faster

C The drone tilts and may lose stable hover

D The drone shuts down automatically

💡 Hint

Think about balance and forces on the drone.

Unequal thrust causes imbalance, making the drone tilt and lose stable hover.

Practice

1. What does the hover condition thrust == weight mean for a drone?

easy

A. The drone's battery is fully charged.

B. The drone will start moving upward quickly.

C. The drone will fall down immediately.

D. The drone stays steady in the air without moving up or down.

Solution

1. Step 1: Understand thrust and weight

   Thrust is the upward force from the drone's propellers, and weight is the downward force due to gravity.

2. Step 2: Analyze the equality condition

   When thrust equals weight, the forces balance, so the drone neither rises nor falls.

3. Final Answer:

   The drone stays steady in the air without moving up or down. -> Option D

4. Quick Check:

   Hover condition means thrust = weight [OK]

Hint: Hover means forces balance: thrust equals weight [OK]

Common Mistakes:

• Thinking thrust > weight means hovering
• Confusing thrust with battery power
• Assuming thrust < weight means hovering

2. Which of the following is the correct way to check if thrust equals weight in drone programming?

easy

A. if thrust == weight:

B. if thrust != weight:

C. if thrust = weight:

D. if thrust => weight:

Solution

1. Step 1: Identify the comparison operator

   In programming, == checks if two values are equal, while = assigns a value.

2. Step 2: Choose the correct syntax

   To check equality, use if thrust == weight: which compares thrust and weight.

3. Final Answer:

   if thrust == weight: -> Option A

4. Quick Check:

   Use '==' for equality check [OK]

Hint: Use '==' to compare values, '=' is for assignment [OK]

Common Mistakes:

• Using single '=' instead of '==' for comparison
• Using '!=' which means not equal
• Using invalid operators like '=>'

3. What will be the output of this code snippet?

thrust = 10
weight = 10
if thrust == weight:
    print('Hovering')
else:
    print('Not hovering')

medium

A. Hovering

B. No output

C. SyntaxError

D. Not hovering

Solution

1. Step 1: Compare thrust and weight values

   Both thrust and weight are set to 10, so thrust == weight is True.

2. Step 2: Determine which branch runs

   Since the condition is True, the code prints 'Hovering'.

3. Final Answer:

   Hovering -> Option A

4. Quick Check:

   10 == 10 is True, so print 'Hovering' [OK]

Hint: Equal values trigger 'Hovering' print [OK]

Common Mistakes:

• Confusing assignment '=' with comparison '=='
• Expecting 'Not hovering' when values are equal
• Missing indentation causing syntax errors

4. Find the error in this code that checks hover condition:

if thrust = weight:
    print('Hovering')

medium

A. Missing colon ':' after if statement

B. Using '=' instead of '==' for comparison

C. Incorrect indentation of print statement

D. Variable names are invalid

Solution

1. Step 1: Check the if statement syntax

   The code uses = which assigns value, not compares values.

2. Step 2: Correct the operator for comparison

   Replace = with == to properly check if thrust equals weight.

3. Final Answer:

   Using '=' instead of '==' for comparison -> Option B

4. Quick Check:

   Use '==' to compare, '=' assigns [OK]

Hint: Use '==' in if conditions, '=' is assignment [OK]

Common Mistakes:

• Confusing '=' and '=='
• Ignoring missing colon errors
• Assuming indentation error instead of operator error

5. You want the drone to print 'Hovering' only when thrust equals weight, and 'Adjusting' otherwise. Which code correctly implements this?

thrust = 15
weight = 15
# Your code here

hard

A. if thrust = weight:
print('Hovering')
else:
print('Adjusting')

B. if thrust != weight:
print('Hovering')
else:
print('Adjusting')

C. if thrust == weight:
print('Hovering')
else:
print('Adjusting')

D. if thrust > weight:
print('Hovering')
else:
print('Adjusting')

Solution

1. Step 1: Use correct equality check

   The condition must use == to check if thrust equals weight.

2. Step 2: Use else for other cases

   If thrust is not equal to weight, print 'Adjusting' to indicate change needed.

3. Final Answer:

   if thrust == weight: print('Hovering') else: print('Adjusting') -> Option C

4. Quick Check:

   Use '==' for equality, else for other cases [OK]

Hint: Use if thrust == weight else for other cases [OK]

Common Mistakes:

• Using '=' instead of '==' in if condition
• Reversing condition with '!='
• Using '>' which is not hover condition