A liquid cools so that its temperature is θ=20+60e−kt after t minutes. After 10 minutes the temperature is 50∘C. Find the exact value of k, and the temperature after 20 minutes.
Salam Academy Original Practice · Proposed mark scheme
A liquid at 100∘C is placed in a room at 20∘C and cools according to dtdθ=−k(θ−20), with t in minutes. After 5 minutes it is at 60∘C. Find the time at which it reaches 30∘C.
Salam Academy Original Practice · Proposed mark scheme
SA-9709-P3-IN-0154 marksL3 ExamCalculatorBy parts
Find ∫xcos2xdx.
Salam Academy Original Practice · Proposed mark scheme
SA-9709-P3-LE-0124 marksL3 ExamCalculatorLinear forms
Variables x and y satisfy y=kax. The graph of lny against x is a straight line through (0,1.2) and (4,3.0). Find k and a, each correct to 3 significant figures.
Salam Academy Original Practice · Proposed mark scheme
A sledge of mass 40 kg starts from rest and slides 30 m down a slope, descending 12 m vertically. A constant friction force of 60 N acts. Find its speed at the bottom, correct to 3 significant figures.
Salam Academy Original Practice · Proposed mark scheme
A block of mass 5 kg rests on a rough horizontal floor with μ=0.4. It is pulled by a force P N at 30∘ above the horizontal and is on the point of moving. Find P, correct to 3 significant figures.
Salam Academy Original Practice · Proposed mark scheme
A (3 kg, 4m s−1) collides directly with B (2 kg) moving at 2m s−1 in the opposite direction. After the collision A moves back at 1m s−1. Find B's speed after the collision.
Salam Academy Original Practice · Proposed mark scheme