Science Assessment Term 3 PDF

Scalar and Vector quantities Scalar- Physical quantities that only have a magnitude. It is described by just one numerical value. Examples: time, speed, volume, and mass Vector- Physical quantities that have a magnitude as well as a direction. They are important in the study of motion. Examples: fo...

Scalar and Vector quantities Scalar- Physical quantities that only have a magnitude. It is described by just one numerical value. Examples: time, speed, volume, and mass Vector- Physical quantities that have a magnitude as well as a direction. They are important in the study of motion. Examples: force, velocity, acceleration, weight, momentum, and friction Formulas- Acceleration: Final speed - initial speed Time taken E.g, An object starts from rest and picks up speed such that its velocity becomes 5 m/s in 10 seconds. It took 10 s to go from 0 m/s to 5 m/s. Then, the rate at which its velocity changes is: (5 m/s – 0)/10 s = 0.5 m/s2. Therefore, its acceleration is 0.5 m/s2. Newton's second law F= force, weight (Newtons) M= Mass (kg) A= acceleration Newton's second law: Force(N)= mass(kg) x acceleration (m/s2) Formulas and examples: Speed triangle: d = total distance travelled sav = average speed t = total time taken I swam 50 metres in 25 seconds. What is the average time? 2m/s Velocity triangle s = displacement vav = average velocity t = time I rolled a ball and it took 3 seconds to be 6 metres away from its original position. What is the ball's average velocity? Acceleration Triangle ∆v = change in velocity a = average acceleration ∆t = change in time Distance time graph- Newton's Laws of Motion- 1. An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force, external force (for e.g gravity, friction a push). 2. The acceleration of an object depends on the mass of the object and the amount of force applied. 3. Whenever one object exerts a force on another object, the second object exerts an equal and opposite on the first. How are Newton's laws of motion and the law of the conservation of energy utilised in the rides at Luna park? Big Dipper The big dipper utilises Newton's first law when the ride is at rest at the boarding platform, which will remain stationary until an external force, in this case the launch mechanism acts upon it to begin its motion. Another way the big dipper utilises Newton's first law is when the train descends from the peak, gravity acts as the external force that accelerates the train down the slope. Once the train starts moving, it will stay in motion due to its inertia, unless acted upon by other forces such as friction or air resistance. Boomerang Newton's second law states that the acceleration of an object depends on the mass of the object and the amount of force applied. The Boomerang utilises this law during its initial descent and the force of gravity, after reaching the top of the initial launch point, the train begins to descend. Gravity is the external force that pulls the ride downward which causes it to accelerate. The acceleration of the ride is proportional to the gravitational force acting on it and is impacted by its mass. Dodgem cars Newton's third law states that if one object exerts a force on another object the second object will exert an equal and opposite force on the first. Luna park’s dodgem cars utilises this third law in which during the impact of two dodgem cars, the force exerted by the first car on the second car is equal in magnitude and opposite in direction to the force exerted by the second car onto the first car. This means that both cars experience the same force yet in different directions which links back to Newton's third law. Extended response- Car safety features are a vital feature that have been implemented into cars and are designed to reduce the impact of collisions on passengers and increase the chances of survival. Understanding these features through the study of Newton's Laws of Motion provides a better view into their purpose and effectiveness. Seatbelts are a prominent safety feature that incorporates Newton's first law of inertia, by restraining the passenger it is able to prevent them from moving forward when the car comes to a sudden stop. For example, if a vehicle comes to an abrupt stop after travelling at a constant velocity, a passenger not wearing a seatbelt would continue moving forward at the same constant velocity, this would cause the passenger to collide with the windshield or the seat in front of them. Wearing a seatbelt secures the passenger, effectively making them a part of the car. This means that during an impact, the driver and passengers will decelerate at the same rate as the car. Crumple Zones are a safety feature that incorporates Newton's third law, If a fast-moving car collides with a solid wall, the force exerted on the wall will be powerful due to the vehicle's mass combined with its acceleration. According to Newton’s Third Law, this same force will be applied in the opposite direction, from the wall back towards the car. This powerful force can cause significant damage to the front of the car. However, a crumple zone at the front helps to absorb some of the impact, reducing the risk of this force reaching and damaging the engine. Car safety features, such as seatbelts and crumple zones, significantly enhance passenger protection by utilising Newton's Laws of Motion. Seatbelts employ Newton's First Law of Inertia to restrain passengers, preventing them from moving forward during sudden stops and reducing injury risk. Crumple zones use Newton's Third Law to absorb collision impact, minimising force transmission to the vehicle's occupants and protecting critical components like the engine. Both features are highly effective: seatbelts cut fatal injury risk by about 45%, while crumple zones ensure controlled deformation, safeguarding the passenger compartment and reducing injury severity during collisions.