Physics paper 1

Working as a Physicist ● Mechanics ● Electric Circuits ● Further Mechanics ● Electric and Magnetic Fields ● Nuclear and Particle Physics

Topic 2: Mechanics

• v2=u2+2as
• S=(u+v)t/2
• s=ut+0.5at2
• v=u+at
• Displacement time graph-Grad= velocity
• Velocity time graph- Grad= Acceleration Area= displacement
• Acelleration time graph- Area= Velocity 
• Scalar quantaty - Only has magnitude
• Vector quantity- Has magnitude and direction
• Vectors can be resolved into horizontal and vertical components
• Projectiles have a u shape under free gravity conditions
  • Horizontal velocity constant
  • Vertical acceleration often g= 9.81ms-2 downwards
  • Max hight has 0ms-1 vertical velocity instantaneous rest
  • if lanched horizontaly no initial vertical component
• Free body force diagrams used to represent forces acting at a point 
• Newtons first law: where a = 0, objects at rest or travelling at constant velocity
• Newtons second law:∑F = ma= I/t where I is impulse
• Newtons third law: If object A exerts a force on object B then object B exerts an equal magnitude force on A in the opposite direction.
• Forces exerted by A and B are newtons third law pairs.
  • They act for the same time
  • Are the same magntiude
  • Act on different objects
  • Act in different directions
  • Act on the same line
• Terminal velocity where there is no resultant force max speed reached.
  • for a falling object drag increaces with speed 
  • When drag force equals the weight there is no resultant force
  • Therefore no more acceleration so the object travvels at a constant velocity.
• Gravitational field strength g=F/m Weight W=mg
• CORE PRACTICAL 1: Determine the acceleration of a freely-falling object.
  • (a) object falling through a trap door (b) object falling through a light gate
  • Draw a diagram
  • Drop the object from rest and record the time taken t for: (a) the sphere to fall to the trap door (b) the dowel to pass through the light gate.
  • Repeat the measurement for (a) and (b) twice more and take the mean value.
  • Measure and record the height h fallen by the object.
  • Repeat the timing of the drop as you vary the height; you should take at least 6 readings
  • using s= ut+0.5at2
  • Plot a graph of t2 (y-axis) against h (x-axis) and work out the gradient m of the line of best fit
  • Calculate g
• Momentum P= mv
• Principle of conservation of linear momentum: Total momentum before a collision or explosion = Total momentum after provided no extenal forces act.
• Moment is the turning effect of a force. Moment = Fx where x is the perpendicular distance between the line of action of the force and the axis of rotation 
•  work ∆W = F∆s where Fis the force in the direction of motion
• Ek=p2/2m
•  ∆Egrav = mg∆h for the difference in gravitational potential energy near the Earth’s surface
• Energy is neither created nor destroyed only transfered usefully or stored
• Power is rate of energy transfer
•  Efficiency=useful energy output/total energy input 

Topic 3: Electric Circuits

• Electric current is the rate of flow of charged particles It=Q
• Potential difference is the energy transfered by each coulomb of charge between…