Mechanics — Variant 2
A Level Mathematics · 9709/42 · Feb/March 2022
Questions
5 of 7 questions shown here, checked against the paper. The others are in the PDF above — they contain diagrams or maths we could not yet verify, and we would rather show you the original than a transcription we are not sure of.
1
A crane is used to raise a block of mass kg vertically upwards at a constant speed through a height of m. There is a resistance to the motion of the block, which the crane does J of work to overcome.
1(a)
[2]
Find the total work done by the crane.
1(b)
[2]
Given that the average power exerted by the crane is kW, find the total time for which the block is in motion.
2
A particle is projected vertically upwards from horizontal ground with speed . reaches a maximum height of m above the ground.
2(a)
[2]
Find the value of .
2(b)
[3]
Find the total time for which is at least m above the ground.
4
The total mass of a cyclist and her bicycle is kg. The cyclist is riding with constant power of W up a straight hill inclined at an angle to the horizontal, where . At an instant when the cyclist's speed is , her acceleration is . There is a constant resistance to motion of magnitude N.
4(a)
[4]
Find the value of .
4(b)
[2]
Find the steady speed that the cyclist could maintain up the hill when working at this power.
5
Four coplanar forces act at a point. The magnitudes of the forces are N, N, N and N. The directions of the forces are as shown in the diagram.
5(a)
[5]
Given that the forces are in equilibrium, find the values of and .
5(b)
[2]
Given instead that , find the value of for which the resultant of the forces is perpendicular to the N force.
6
A cyclist starts from rest at a fixed point and moves in a straight line, before coming to rest seconds later. The acceleration of the cyclist at time s after leaving is , where for .
6(a)
[4]
Find the value of .
6(b)
[3]
Find the maximum speed of the cyclist.
6(c)
[4]
Find an expression for the displacement from in terms of . Hence find the total distance travelled by the cyclist from the time at which she reaches her maximum speed until she comes to rest.
Published by Cambridge Assessment International Education. Reproduced for study use.