Paper 5 May/June 2011 MATHEMATICS (9709/51) A Levels
لطفا برای اطمینان از عملکرد و تجربه بهتر از مرورگرهای مدرن و به روز مانند کروم یا فایرفاکس استفاده کنید.

A load of mass $1250{\text{ }}kg$ is raised by a crane from rest on horizontal ground, to rest at a height of $1.54{\text{ }}m$ above the ground. The work done against the resistance to motion is $5750{\text{ }}J$.
a) Find the work done by the crane.
b) Assuming the power output of the crane is constant and equal to $1.25{\text{ }}kW$, find the time taken to raise the load.