FORCE, MASS AND ACCELERATION
3 marks · HardA company wants to design an emergency stopping system for lightweight drones. The system applies the same unbalanced force to drones of different masses to bring them to a stop in emergencies.
Explain, using the formula , why lighter drones can be stopped more quickly than heavier drones by the same force. In your answer, refer to how acceleration depends on mass.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
According to , if the same unbalanced force is applied, the acceleration is inversely proportional to mass because . Therefore, lighter drones (with smaller mass) will have a greater acceleration (or deceleration) for the same force, allowing them to be stopped more quickly than heavier drones, which will decelerate less for the same force.
Must show: State that for the same force, acceleration is larger when mass is less, Reference , Link to stopping more quickly (greater deceleration)
Also accept: States that lighter drones have greater acceleration or deceleration for the same force; Explains in terms of proportionality or formula
Common mistakes: States only that force is same without linking to acceleration; Confuses mass and acceleration proportionality
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Mentions or uses the formula or
B2 · 1 mark · Correctly states that for a given force, acceleration increases as mass decreases (inverse proportionality)
B3 · 1 mark · Links greater acceleration/deceleration to being able to stop more quickly (clear logic chain)
Worked solution
Using , for a given force, acceleration . This means that if mass is smaller, the acceleration (deceleration) is larger. So, lighter drones with less mass will experience a bigger deceleration when the same stopping force is applied. Therefore, lighter drones can be stopped more quickly than heavier drones using the same force.