Moderate -0.8 This is a straightforward application of the work formula W = Fs cos θ, requiring only the identification that distance = speed × time (16m), then calculating 25 × 16 × cos(20°). It involves basic recall and one simple multi-step calculation with no problem-solving insight needed, making it easier than average.
1 One end of a light inextensible string is attached to a block. The string is used to pull the block along a horizontal surface with a speed of \(2 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). The string makes an angle of \(20 ^ { \circ }\) with the horizontal and the tension in the string is 25 N . Find the work done by the tension in a period of 8 seconds.
1 One end of a light inextensible string is attached to a block. The string is used to pull the block along a horizontal surface with a speed of $2 \mathrm {~m} \mathrm {~s} ^ { - 1 }$. The string makes an angle of $20 ^ { \circ }$ with the horizontal and the tension in the string is 25 N . Find the work done by the tension in a period of 8 seconds.
\hfill \mbox{\textit{CAIE M1 2011 Q1 [3]}}