An internet shopping company is planning to use drones to deliver packages - Scottish Highers Physics - Question 2 - 2018

The power dissipated by the motor can be calculated using the formula:

$P = \frac{V^2}{R}$

where:

• $V$ is the voltage supplied (12V)
• $R$ is the resistance (9.6Ω)

Substituting the values: $P = \frac{(12)^2}{9.6} = \frac{144}{9.6} = 15 \, W$

Thus, the power dissipated by the motor is $15 \, W$.

When the cable breaks, the upward force produced by the drone remains constant. However, the weight of the package no longer has the support from the cable, leading to an imbalance. Therefore, the remaining force from the drone causes the drone to accelerate upwards. In this case, the upward force is still acting while the weight is effectively reduced to just the gravitational force on the package, which could lead to an increasing acceleration as the net force is applied upward.

To find the tension in each cord, we first need to calculate the weight of the package:

$W = mg = 3.4 \, kg \times 9.8 \, m/s^2 = 33.32 \, N$

Since the two drones are working together to lift the package, the tension in each cord can be evaluated. Assuming the cords are symmetrically placed:

The total upward force must equal the weight of the package: $2T = 33.32 \, N$

From this, we can find the tension in each cord: $T = \frac{33.32}{2} = 16.66 \, N$

Thus, the tension in each cord is approximately $16.66 \, N$.