Moderate -0.3 This is a straightforward application of Newton's second law combined with a single SUVAT equation. Students must find acceleration from kinematics (a = Δv/Δt = 0.4 m/s²), then apply F_net = ma to get F - 1.5 = 0.2(0.4), solving for F = 1.58 N. It's slightly easier than average because it's a direct two-step problem with no conceptual subtlety, though it does require understanding force direction and net force.
1 A particle of mass 0.2 kg moving in a straight line experiences a constant resistance force of 1.5 N . When the particle is moving at speed \(2.5 \mathrm {~m} \mathrm {~s} ^ { - 1 }\), a constant force of magnitude \(F \mathrm {~N}\) is applied to it in the direction in which it is moving. Given that the speed of the particle 5 seconds later is \(4.5 \mathrm {~m} \mathrm {~s} ^ { - 1 }\), find the value of \(F\).
1 A particle of mass 0.2 kg moving in a straight line experiences a constant resistance force of 1.5 N . When the particle is moving at speed $2.5 \mathrm {~m} \mathrm {~s} ^ { - 1 }$, a constant force of magnitude $F \mathrm {~N}$ is applied to it in the direction in which it is moving. Given that the speed of the particle 5 seconds later is $4.5 \mathrm {~m} \mathrm {~s} ^ { - 1 }$, find the value of $F$.\\
\hfill \mbox{\textit{CAIE M1 2018 Q1 [4]}}