The diagram shows the forces acting on a child on a playground slide. Air resistance is negligible.
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(a) The mass of the child is 40 kg.
(i) Calculate the size of the force W. [1]
(ii) Describe the force that, along with W, makes up the ‘equal and opposite pair’ of forces described by Newton’s third law. [1]
(b) The size of the friction force is 90 N.
(i) Calculate the component of W parallel to the slide. [2]
(ii) Calculate the acceleration of the child. [3]
(c) The slide is 5.5 m long. If the child maintains this acceleration, calculate her speed at the bottom. [3]
