A 0.20 kg mass is suspended from a spring - AQA - A-Level Physics - Question 14 - 2019 - Paper 1

According to Newton's second law: $F_{net} = ma$
Where:

• $F_{net}$ is the net force acting on the mass, and for the 0.20 kg mass, this is the upward force (which is zero, because the thread is cut) minus its weight.
• Therefore: $F_{net} = 0 - 1.96 \, \text{N} = -1.96 \, \text{N}$ Substituting into Newton's second law gives: $-1.96 \, \text{N} = 0.20 \, \text{kg} \times a$ To find the acceleration, rearrange the equation: $a = \frac{-1.96 \, \text{N}}{0.20 \, \text{kg}} = -9.8 \, \text{m/s}^2$

Since the negative sign indicates the direction of acceleration is downward, the upward acceleration of the 0.20 kg mass at the instant the thread is cut is:

$a = 9.8 \, \text{m/s}^2$

Hence, the upward acceleration is 9.8 m/s².