1 Racing cars are designed with a low centre of gravity mainly to: A Increase their speed B Improve their stability C Reduce their mass D Increase their fuel efficiency
3 A free-body diagram shows: A Only the forces acting on an object B Only the forces exerted by the object C All forces in the universe D Only the weight of the object
4 In an isolated system, the total momentum: A Increases with time B Decreases with time C Remains constant D First increases then decreases
5 Newton's laws of motion fail to explain motion at: A Low speeds B Very high speeds close to the speed of light C Everyday speeds D Zero acceleration
6 For a body to be in equilibrium under the action of several coplanar forces, the sum of clockwise moments about any point must be: A Greater than anticlockwise moments B Less than anticlockwise moments C Equal to anticlockwise moments D Zero only if no forces act
7 The weight of an object is given by W = mg. What does 'g' represent in this formula? A Gravitational constant B Acceleration due to gravity C Gravitational force D Mass of the Earth
8 What is the net force on an object moving with constant velocity? A Zero B Equal to its weight C Equal to its mass D Infinite
9 A body is in static equilibrium when it is: A Moving with constant velocity B At rest and remains at rest C Accelerating D Rotating with constant angular velocity
10 In a free-body diagram, the force exerted by a surface on an object perpendicular to the surface is called: A Weight B Normal reaction C Friction D Tension
11 Two equal and opposite parallel forces acting at different points form a: A Couple B Single force C Balanced force D Resultant force
12 The perpendicular distance from the pivot to the line of action of force is called: A Moment arm B Force arm C Couple arm D Torque arm
13 A racing car is made low and wide mainly to: A Increase its speed B Lower its centre of gravity and increase stability C Reduce its mass D Increase its air resistance
14 Airbags in cars increase the time of impact to: A Increase the force on passengers B Decrease the force on passengers C Increase the momentum D Decrease the impulse
15 A couple consists of two forces which are: A Equal in magnitude, same direction, different lines of action B Equal in magnitude, opposite direction, same line of action C Equal in magnitude, opposite direction, different lines of action D Unequal in magnitude, opposite direction, different lines of action
16 The first condition for equilibrium is that the net force acting on a body must be: A Maximum B Minimum C Zero D Constant
17 The centre of gravity of a uniform meter rod lies at: A 10 cm mark B 50 cm mark C 90 cm mark D 100 cm mark
18 A force of 10 N is applied at a distance of 2 m from the pivot. What is the moment of the force? A 5 N m B 10 N m C 20 N m D 40 N m
20 A force of 20 N acts at a perpendicular distance of 0.5 m from a pivot. What is the moment of the force? A 40 N m B 10 N m C 20.5 N m D 0.025 N m
21 Which type of friction is generally the smallest? A Static friction B Sliding friction C Rolling friction D Kinetic friction
22 In a free-body diagram, the force that opposes the motion of an object is represented by: A Weight B Normal reaction C Friction D Tension
23 In a see-saw, a 30 kg child sits 2 m from the pivot. To balance it, a 60 kg child should sit at: A 0.5 m B 1 m C 2 m D 4 m
24 A body is in dynamic equilibrium when it moves with: A Increasing velocity B Constant velocity C Constant acceleration D Zero velocity
25 A rocket moves forward because the exhaust gases are pushed backward. This is an example of: A Newton's first law B Newton's second law C Newton's third law D Law of gravitation