A car against a resistance, and motion on rough and smooth inclined planes
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The teaching part (1 min) is free to watch. A free account opens the whole lecture: 6 practice questions, 2 real past-paper questions with the answers explained, the mistakes that lose marks, the full-marks tip, a one-card summary and a quick quiz.
What this lecture covers
- Force along a line
- Newton along a line
- A minibus
Read the transcript of the teaching part
Last time
Before we start: last time, in Particles connected by a string, over a pulley, and with a plane, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.
Force along a line
A minibus on a flat road. A block on a slope. Both come down to one line of motion, one equation: the net force equals mass times acceleration. The skill is choosing the line, listing every force along it, and getting the signs right. On a slope, the line is up or down the plane.
Newton along a line
Choose the direction of motion as positive. List every force along it: driving force, resistance, the component of weight. Add them with signs: forces with the motion are positive, against it negative. Set the sum equal to mass times acceleration. At constant speed, acceleration is zero. Then the driving force equals the resistance.
A minibus
A minibus of mass 4000 kilograms has resistance 900 newtons. It accelerates at 0.5. Driving force F minus 900 equals 4000 times 0.5, so F is 2900. At a constant speed of 25, the driving force equals the resistance, 900. Power is force times speed: 900 times 25, which is 22 500 watts.
How often it comes up
How often Cambridge has asked each part, counted by ExamYard from every past paper in its question bank: Motion on a rough inclined plane.
The whole chapter: Newton's Laws of Motion.
Chapter 4.4: Newton's laws of motion
- Particles connected by a string, over a pulley, and with a plane 6 min
- A car against a resistance, and motion on rough and smooth inclined planes 6 min
- A vehicle towing a trailer, vertical motion against a resistance, and a lift 6 min
Also for A Level Maths 9709 Paper 4
Which topics come up most in A Level Maths 9709 Paper 4 past papers, counted from every paper since 2004.