Work, energy and powerEdexcel International A Level Further Maths: Mind map

Exam questions on Work, energy and power

1. A car of mass $1200$ kg moves along a straight horizontal road. The engine works at a constant power of $24$ kW and the resistance to motion is a constant $800$ N.
   Find the increase in the car's kinetic energy as its speed increases from $15$ m s$^{-1}$ to $30$ m s$^{-1}$.2 marks
2. A box of mass $5$ kg is pulled from rest up a line of greatest slope of a rough plane inclined at $20^\circ$ to the horizontal, by a constant force of $40$ N acting parallel to the plane. A constant frictional force of $8$ N opposes the motion. Take $g=9.8$ m s$^{-2}$. The box moves $6$ m up the plane.
   Find the speed of the box after it has moved $6$ m.2 marks
3. A lorry of mass $6000$ kg moves up a straight road inclined at an angle $\alpha$ to the horizontal, where $\sin\alpha=\frac{1}{20}$. The resistance to motion is a constant $1500$ N. Take $g=9.8$ m s$^{-2}$.
   The lorry travels up the road at a constant speed of $12$ m s$^{-1}$. Find the power of the engine.3 marks