JPJC 2026 Forces and Moments Assignment

1 JURONG PIONEER JUNIOR COLLEGE 8867 H1 PHYSICS FORCES AND MOMENTS ASSIGNMENT 1 (a) A truck of mass 39000 kg is stationary on a hill with a gradient of 15°. The three forces acting on the truck are its weight, a frictional force parallel to the road and a reaction force normal to the road. (i) Draw a triangle of forces to show that the truck is in equilibrium. Label each force. [2] (ii) Determine the numerical value of each of the three forces. [3]

2 (b) A flat root, shown in Fig. 1.1, of width 5.6 m between walls, is subjected to the following loading. The uniformly distributed weight of roof structure is 55 kN. The load placed on roof 1.6 m from wall A is 10 kN. Calculate the forces provided by each wall. [4] 2 Fig. 2.1 shows a uniform metal beam pivoted at one end and held in equilibrium in a horizontal plane by a cable attached to its other end. Fig. 2.1 The beam has mass 210 kg and length 8.0 m. The cable makes an angle of 32 ° to the beam and has tension T. A pile of bricks of total mass 150 kg is placed on the beam. (a) On Fig. 2.1, draw labelled arrows to show three other forces acting on the beam. [2] Fig. 1.1

3 (b) Describe and explain what would happen to the tension T in the cable as the pile of bricks is slowly moved towards the end P of the beam. [2] (c) The pile is placed at a distance of 5.3 m from the end P. Calculate the tension T in the cable. [2]