# Section 1: Forces and Motion

## 1.32 understand gravitational field strength, g, and recall that it is different on other planets and the moon from that on the Earth

1.32 understand gravitational field strength, g, and recall that it is different on other planets and the moon from that on the Earth The strength of gravity on a planet or moon is called its gravitational field strength. But this force depends upon The masses of the...

## 1.33 explain that gravitational force

1.33 explain that gravitational force causes moons to orbit planets causes the planets to orbit the sun causes artificial satellites to orbit the Earth causes comets to orbit the sun Planets are held in orbit by the gravitional pull of the Sun. Similarly comets orbit...

## 1.29 describe experiments to investigate how extension varies with applied force for helical springs, metal wires and rubber bands

1.29 describe experiments to investigate how extension varies with applied force for helical springs, metal wires and rubber bands Experiment: Investigating extension with applied force in spring Apparatus: Spring/Wire/Rubber-band, Scale, Some masses, Clamp and stand,...

## 1.28 understand that the upward forces on a light beam, supported at its ends, vary with the position of a heavy object placed on the beam

1.28 understand that the upward forces on a light beam, supported at its ends, vary with the position of a heavy object placed on the beam An object weighing 400 N is placed in the middle of the beam. The beam is not moving,so the upward and downward forces must be...

## 1.31 describe elastic behaviour as the ability of a material to recover its original shape after the forces causing deformation have been removed.

1.31 describe elastic behaviour as the ability of a material to recover its original shape after the forces causing deformation have been removed. Objects showing elastic behaviour has the ability to return to its original shape after the forces causing its shape are...

## 1.30 understand that the initial linear region of a force-extension graph is associated with Hooke’s law

1.30 understand that the initial linear region of a force-extension graph is associated with Hooke’s law Hooke’s law, “Within the elastic limit, extension is directly proportional to the load i.e. e α f” Hooke measured the increase in length (extension) produced by...

## 1.27 know and use the principle of moments for a simple system of parallel forces acting in one plane

1.27 know and use the principle of moments for a simple system of parallel forces acting in one plane Here, the pivot is placed in the centre of the beam which balances it upon the pivot. All the weight is acting upon it. If the pivot is moved leftwards, the distance...

## 1.22 use the conservation of momentum to calculate the mass, velocity or momentum of objects

1.22 use the conservation of momentum to calculate the mass, velocity or momentum of objects Force x time = increase in momentum If a moving object hits another slow or stationary object, it will result an equal force to both of the objects (according to Newton’s...

## 1.23 use the relationship between force, change in momentum and time taken

1.23 use the relationship between force, change in momentum and time taken Initial momentum of object= mu Final momentum= mv Therefore increase in momentum = mv-mu Rate of increase of momentum= (mv-mu)/t (mv – mu)/t m(v-u)/t ma=Force Force = Rate of increase of...

## 1.24 demonstrate an understanding of Newton’s third law

1.24 demonstrate an understanding of Newton’s third law Newton’s thirds law: “For every action there is an equal and opposite reaction.” Newton’s third law states four characteristics of forces: Forces always occur in pairs (action and reaction force.) The action and...

## 1.25 know and use the relationship between the moment of a force and its distance from the pivot

1.25 know and use the relationship between the moment of a force and its distance from the pivot moment = force × perpendicular distance from the pivot moment =F x d The turning effect of a force about a hinge or pivot is called its moment. It is measured in Newton...

## 1.26 recall that the weight of a body acts through its center of gravity

1.26 recall that the weight of a body acts through its centre of gravity The centre of gravity of an object is the point where the whole weight appears to act. So if we support the centre of gravity of the object, the object wont fall no matter how wide it is. Because...

## 1.21 use the idea of momentum to explain safety features

1.21 use the idea of momentum to explain safety features Objects in a car have mass, speed and direction. If the object, such as a person, is not secured in the car they will continue moving in the same direction (forward) with the same speed (the speed the car was...

## 1.17 describe the forces acting on falling objects and explain why falling objects reach a terminal velo

1.17 describe the forces acting on falling objects and explain why falling objects reach a terminal velocity In a free falling object two types of force acts: Drag and Weight. The size of the drag force acting on an object depends on its shape and its speed. If the...

## 1.18 describe experiments to investigate the forces acting on falling objects, such as sycamore seeds or parachutes

1.18 describe experiments to investigate the forces acting on falling objects, such as sycamore seeds or parachutes Experiment: Measuring the force of a falling ball using light gate Apparatus required: Cylinder, light gate, data logger, electric balance First, we...

## 1.19 describe the factors affecting vehicle stopping distance including speed, mass, road condition and reaction time

1.19 describe the factors affecting vehicle stopping distance including speed, mass, road condition and reaction time The stopping distance is the sum of Thinking distance and Braking distance. Thinking Distance: The distance travelled after seeing an obstacle and...

## 1.20 know and use the relationship between momentum, mass and velocity

1.20 know and use the relationship between momentum, mass and velocity Momentum is a quantity possessed by masses in motion. Momentum is measure of how difficult it is to stop something that is moving. We calculate the momentum of a moving object using the formula:...

## 1.13 find the resultant force of forces that act along a line

1.13 find the resultant force of forces that act along a line Forces which act along a straight line can be added if the forces are in the same direction or subtracted if the forces are in the opposite direction. The force that you get after adding or subtracting is...

## 1.15 know and use the relationship between unbalanced force, mass and acceleration

1.15 know and use the relationship between unbalanced force, mass and acceleration Balanced and Unbalanced force: When a force acting on an object is equal to the force opposing the object the forces are “balanced.”In this case the object will not move. If a force...

## 1.16 know and use the relationship between weight, mass and g

1.16 know and use the relationship between weight, mass and g Weight is the pull of earth. To calculate it, use the formula: Weight = mass x gravitional acceleration W =mg In earth g= 10 m/s2 if there is no opposite force.

## 1.8 determine the distance traveled from the area between a velocity-time graph and the time axis.

1.8 determine the distance travelled from the area between a velocity-time graph and the time axis. Distance can be determined by finding the area under a velocity-time graph as shown below Distance travelled = area under the graph = 1/2(a+b)h = 1/2(100 + 40) x 150 =...

## 1.10 identify different types of force such as gravitational or electrostatic

1.10 identify different types of force such as gravitational or electrostatic Different sorts of Force: Gravitional force or weight: The pull of earth due to gravity. Normal Reaction: Simple reaction that stops something when to apply force to it. E.g.: A book is kept...

## 1.11 distinguish between vector and scalar quantities

1.11 distinguish between vector and scalar quantities Scalar quantities are physical quantities that have magnitude only. Vector quantities however are physical quantities that possess both magnitude as well as direction. Scalar Vector Mass Displacement Time Velocity...

## 1.12 understand that force is a vector quantity

1.12 understand that force is a vector quantity Force is a vector quantity due to the following reasons - It has magnitude i.e has the value of its size. It has direction. When applied force, an object moves with particular motion in a fixed direction. E.g:...

## 1.14 understand that friction is a force that opposes motion

1.14 understand that friction is a force that opposes motion Friction is the force that causes moving objects to slow down and finally stop. The kinetic energy of the moving object is converted to heat as work is done by the friction force. Friction occurs when solid...

## 1.5 know and use the relationship between acceleration, velocity and time

1.5 know and use the relationship between acceleration, velocity and time Acceleration is the rate at which objects change their velocity. The rate of decease of velocity is called deceleration. It is just a negative acceleration. It is defined as follows:...

## 1.7 determine acceleration from the gradient of a velocity-time graph

1.7 determine acceleration from the gradient of a velocity-time graph Acceleration = gradient = (y2 - y1)/(x2 - x1 ) = (200-0)/(50-0) = 4 ms2

## 1.4 describe experiments to investigate the motion of everyday objects such as toy cars or tennis balls

1.4 describe experiments to investigate the motion of everyday objects such as toy cars or tennis balls Experiment: Measuring speed using light gate Attach a cart of measured length centrally to the top of the toy car. Air track ensures a frictionless way for the toy...

## 1.3 know and use the relationship between average speed, distance moved and time

1.3 know and use the relationship between average speed, distance moved and time Speed: Speed is defined as the rate of change of distance. In other words, speed is the distance moved per unit time. It tells us how fast or slow an object is moving. Average speed:...