<p>14) Complete the table below to identify the physical quantities as scalars or vectors </p><p>Physical quantity Scalar or vector </p><p>Speed </p><p>Velocity </p><p>Distance </p><p>Force [2]</p><p>15) Diagram A shows a uniform rod balanced at its centre. The 10 N weight and the sandbag are positioned at equal distances from the pivot.</p><p>10 N pivot sandbag</p><p>DIAGRAM A</p><p>(a) What is the weight of the sandbag and its contents?...... N</p><p>[1]</p><p>A hole now appears in the sandbag and sand begins to trickle out.</p><p>(b) In what direction (clockwise or anticlockwise) will the rod tip as a result of the sand trickling out?</p><p>...... </p><p>[1]</p><p>(c) In what direction (to the left or to the answer) must the 10 N weight move along the rod, if the rod is to return to the original horizontal (level) position?</p><p>...... </p><p>[1] 16) The diagram below shows a car-park barrier.</p><p>1.35 m 0.9 m</p><p>STOP</p><p> pivot supporting F 150 N pillar</p><p>The weight of the barrier is 150 N and its centre of gravity is 0.9 in from the pivot.</p><p>(a) Calculate the size of the clockwise moment produced by the barrier’s weight about the pivot.</p><p>Show clearly your working out.</p><p>Clockwise Moment = ...... </p><p>[3]</p><p>(b) Use your answer to part (a) to calculate the size of the force F on the left of the pivot which will just lift the barrier off the supporting pillar.</p><p>Show clearly your working out.</p><p>Force = ...... N</p><p>[3] 17) As a car races round a circular track, it experiences a centripetal force. In the diagram below the car is represented by a large black dot.</p><p>(a) Mark clearly with an arrow labelled F, on the diagram below, the direction of the centripetal force.</p><p> sports car</p><p> direction of motion</p><p> centre of circular track</p><p>[1]</p><p>(b) What provides the force which causes the centripetal force to keep the car moving in a circle.</p><p>...... </p><p>[1]</p><p>(c) The car races around the track at a constant speed. Explain briefly why the car’s velocity is continually changing. </p><p>...... </p><p>...... [1] 18) A steel spring is tested in the laboratory by loading weights onto it and measuring the extension produced by the weights. The graph shows a plot of weight against extension. The spring is 12 cm long before any weight is added.</p><p>Spring</p><p>Weights</p><p>50</p><p>40</p><p>30 Weight in N</p><p>20</p><p>10</p><p>0 0 1 2 3 4 5 Extension in cm</p><p>(a) The extension is directly proportional to the weight. From the graph, give two reasons why we know this to be the case.</p><p>(i) ...... </p><p>(ii) ...... </p><p>[1] (b) What is the total length of the spring when a weight of 28 N is added?</p><p>Length ...... cm [2]</p>