Welcome to your Forces and Moments(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. The figure below shows a see-saw which is exactly in balance. The weight of the people sitting on it are 50kg, Xkg and 15kg as shown. They sit at distance of 1.5m, 1.5m and 2m from the pivot respectively. The value of X is impossible to find 70 30 26.5 35 2. An object is acted upon by a system of parallel forces causing the object to be in static equilibrium. Which of the following statements is NOT correct? the sum of the forces in one direction must be equal to the sum of the forces in the opposite direction all the parallel forces must be equal in magnitude and direction the algebraic sum of all the moments of the forces is zero the resultant of the parallel forces is zero 3. A man standing on a lift that is descending does not feel any weight because there is no reaction from the floor of the lift there is no gravitational pull on the man in the lift the lift is in vacuum the inside of the lift is air tight 4. The limiting frictional force between two surfaces depends onI. the normal reaction between the surfacesII. the area of surfaces in contactIII. the relative velocity between the surfacesIV. the nature of the surfaces I & IV only I & III only I only III only II only 5. A boy pulls a nail from the wall with a string tied to the nail. The string is inclined at an angle of 60° to the wall. If the tension in the string is 4N, what is the effective force used in pulling the nail? 4√3N 4N 2√3N 2N 8N 6. The value of T in the figure below is 40N 11.8N 20N 10N 7. A technician applied a force of 250N at the end of a spanner of length 0.25m in order to loosen a nut. Determine the moment applied to the nut. 625Nm 1000Nm 62.5Nm 10Nm 8. Kafeel pulls a toy car weighing 3kg along a cement floor. If g = 10m/s² and the coefficient of friction is 0.5, the minimum force required to move the toy car is 60.0N 3.0N 5.0N 10.0N 15.0N 9. A mass of 2kg on a surface (μ = 1/2) is connected to a second mass of 4kg over a frictionless pulley as shown in the diagram. If the acceleration due to gravity is 9.8m/s², then the masses will accelerate at 19.6m/s² remain stationary accelerate at 4.9m/s² accelerate at 39.2m/s² accelerate at 9.8m/s² 10. An 80mm column of a liquid is balanced by 120mm column of water in a Hare's apparatus. Calculate the density of the liquid (density of water = 1000kg/m³) 1500kg/m³ 150kg/m³ 66.7kg/m³ 666.7kg/m³ 11. In the diagram below, the hanging mass M2 is adjusted until M1 is on the verge of sliding. The co-efficient of static friction between the mass M1 and the table is M1 / M2 M1g / M2 M2 / M1 M2g / M1 12. Find the resultant 3N, N 75.2° E 5N, N 65° W 15N, S 43.4° W 17N, S 61.9° E 13. When three coplanar non parallel forces are in equilibriumI. they can be represented in magnitude and direction by the three sides of a triangle triangle taken in orderII. their lines of action meet at a point III. the magnitude of any one force equals the magnitude of the resultant of the other twoIV. any one force is the equilibrant of the other two.Which of the statements above are correct? II & III only I, II, III & IV I & II only I, III & IV only II, III & IV only 14. In the above diagram, the block just moves when the spring balance reads 15.0N. What is F? 0.6N 10.0N 375.0N 40.0N 15.0N 15. A weight of 1000g hangs from a lever 20cm to the right of the fulcrum. At the left is a 500g weight 20cm from the fulcrum. If a 200g weight is Ycm away from the fulcrum, what is the value of Y that will make the lever balance? 70cm 20cm 10cm 30cm 50cm 16. A body of mass 6kg rests on an inclined plane. The normal reaction is R and the limiting frictional force is F as shown in the diagram. If F is 30N and g = 10m/s², then the angle of inclination θ is 75° 60° 30° 15° 17. A box of mass 40kg is being dragged along the floor by a rope inclined at 60° to the horizontal. The frictional force between the box and the floor is 100N and the tension on the rope is 300N. How much work is done in dragging the box through a distance of 4m? 200J 400J 100J 680J 18. Calculate the apparent weight loss of a man weighing 70kg in an elevator moving downwards with an acceleration of 1.5m/s². (g = 10m/s²) 105N 581N 686N 595N 19. An object of mass 20kg slides down an inclined plane at an angle of 30° to the horizontal. The coefficient of static friction is 0.3 0.2 0.5 0.6 20. In the diagram below, a lever of length 200m is used to lift a load of mass 180kg. The pivot at P is 20m from the load. What minimum force, F, must be applied at the end of the lever? 9N 20N 18N 200N 21. A block of mass M is held in equilibrium against a vertical wall by a horizontal force. If the co-efficient of friction between the block and the wall is μ, the minimum value of the horizontal force is mg/μ μmg (1 + μ)mg (1 - μ)mg 22. A body rolls down a slope from a height of 100m. Its velocity at the foot of the slope is 20m/s. What percentage of its initial potential energy is converted into kinetic energy? 35% 20% 15% 40% 23. A uniform meter rule QR is balanced on a knife edge which is 55cm from R. When a mass of 10g is hung at P as shown below, the mass of the meter rule is 35g 550g 70g 350g 24. A block of mass 50kg slides down a plane inclined at an angle of 30° to the horizontal. If the co-efficient of friction is 0.4, calculate the frictional force between the two surfaces. (g = 10m/s²) 173.21N 100.00N 62.50N 200.00N 25. A body of mass 10kg on a smooth inclined plane is connected over a smooth pulley to a mass of 15kg as shown. The acceleration of the system in terms of g is g 8g/25 2g/5 g/2 3g/4 1 out of 25 Time is Up! Time's up