A rocket of mass 12 000 kg accelerates vertically upwards from the surface of the Earth at 1.4 m s² - AQA - A-Level Physics - Question 20 - 2017 - Paper 1

Using Newton's second law, the net force ($F_{net}$) needed to accelerate the rocket upwards at $1.4 \, \text{m/s}^2$ is given by:

$F_{net} = ma$

where:

• $m = 12,000 \, \text{kg}$ (mass of the rocket)
• $a = 1.4 \, \text{m/s}^2$

Therefore,

$F_{net} = 12,000 \, \text{kg} \times 1.4 \, \text{m/s}^2 = 16,800 \, \text{N}$.

The thrust ($T$) of the rocket must overcome both its weight and provide the net force for the upward acceleration. Hence, it can be expressed as:

$T = W + F_{net}$

Where:

• $W = 117,600 \, \text{N}$
• $F_{net} = 16,800 \, \text{N}$

Thus,

$T = 117,600 \, \text{N} + 16,800 \, \text{N} = 134,400 \, \text{N}$.

Now, converting this into scientific notation gives us:

$T = 1.344 \times 10^5 \, \text{N}$.

Upon selecting the closest answer from the options provided, the correct answer is:

C) 1.3 × 10^5 N.