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**furor celtica** im not sure where to post this cos it includes mechanics formulae but im sure most of you have done mechanics as well since it is often included in maths programmes

so

a load of weight 7 kN is being raised from rest with constant acceleration by a cable. after the load has been raised 20 metres, the cable suddenly becomes slack. the load continues upwards for a distance of 4 metres before coming to instantaneous rest. Assuming no air resistance, find the tension in the cable before it became slack.

so obviously T = 7000 N + a(700), a being acceleration

but i can't seem to find this acceleration; ive tried using a velocity-time graph but there are too many unknowns for me; i am also a bit confused by what is meant by 'instantaneous' rest: does this mean constant velocity for 4 metres and then boom the graph line goes vertical?