AQA GCSE Changes to Momentum(Physics)
Changes to Momentum
When a force acts on an object that is moving, or can move, there is a change in momentum.
Lets look at why……..
Newton’s 2nd Law
Newtons 2nd law is
Force = mass x acceleration
So, when a force is applied to an object that has a mass, the object will accelerate, such as shown below.
In the example above the man is exerting a force on the front of the car, so the car will start to accelerate backwards, towards the left.
Acceleration
In the earlier part of the course, we looked at the formula for acceleration and velocity
Combining the equations!
We can now combine both the F = mass x acceleration (F=ma) and acceleration = change in velocity/change in time (a =Δv/Δt) equations into one equation.
Make sure you learn the equation in the red box, it is often linked to impact force questions.
Remember that mass x velocity = momentum. This is what is present in the top line of the formula in the red box.
On the bottom of the formula in the red box is change in time.
So, this means that Force is equal to change in momentum divided by time.
When a quantity is divided by time, it becomes a rate.
So, force is equal to the rate of change of momentum!
Example calculation
1. A car of mass 950kg is travelling at 9m/s and collides with a stationary car in front. The collision time is 0.5 seconds. Calculate the impact force the occupants of the car experience.
Practice Question
1.When a force acts on an object, which can move, how will it affect the momentum of the object.
2. State Newton’s 2nd law
3. State the formula that links acceleration to velocity
4. State the equation that links Force to change in momentum and time taken
5.A 0.2 kg tennis ball moving at 15 m/s is caught in 0.05 s. What is the average force exerted?
Absorption and Emission of EM Radiation
JJ Thomson and Plum pudding model
Ernest Rutherford and the Nuclear Model
Niels Bohr changing the Nuclear Model
Discovering the Proton and Neutron
Measuring radiation from radioactivity
Radiation types and properties
Random nature of radioactive decay
Radioactive contamination or irradiation
Hazards of contamination and irradiation
Studies on the effects of radiation on humans
Different half lives of radioactive isotopes
Nuclear Fission Chain Reaction
Writing nuclear fission equations
Accordion Content
Accordion Content