Procedure Find the mass of both trolleys using an electronic balance. Set up apparatus as illustrated in Fig 3.2 with both trolleys stationary. Push trolley 1 and allow it to collide with and stick to trolley 2. Use the motion detector to measure the velocities of the trolleys before and after the collision.
Observation
The momentum of trolley 1 before the collision is equal to the momentum of the combined trolley 1 and 2. Conclusion
Momentum is conserved during this collision. Force
FORCE A force (F) is that which can cause acceleration.
It is a vector quantity with an SI unit of newton (N).
1 newton is the amount of force that will cause a body of mass 1 kilogram to accelerate by 1 metre per second squared. 1 N 1 kg m s2
SIR ISAAC NEWTON, 1642–1727 (ENGLISH)
Arguably the most influential scientist of all time, he developed calculus, the law of universal gravitation, the laws of motion and proposed corpuscular theory of light. The SI unit of force is named in his honour.
LAWS AND PRINCIPLES
Newton’s Laws of Motion Sir Isaac Newton described the concept of force in his three laws of motion.
Law 1 A body will remain at rest or continue moving at constant velocity unless acted upon by an unbalancing external force.
Law 2 The rate of change of momentum is proportional to the applied force and takes place in the direction of the force.
Law 3 For every action there is an equal and opposite reaction, action and reaction do not happen on the same body.
SCIENCE,TECHNOLOGY & SOCIETY Law 1:
Seatbelts are used to stop passengers in cars from continuing at constant velocity when the car decelerates rapidly (or crashes!)
Law 2: When a football is kicked, a force is applied on the ball by the player’s foot; the greater the force the greater the acceler- ation. For an example of a football accelerating, check out Cristiano Ronaldo’s free kick for Manchester United against Portsmouth in the 2007/08 Premiership season on YouTube.
