Dynamics Section Flashcards
What is velocity?
Rate of change of displacement
What is the definition for Conservation of energy?
Energy cannot be created or destroyed, only converted from one form to another.
What is the definition for 1 Newton?
One newton is defined as the force required to make a 1kg object accelerate at 1ms-2.
What is the resultant of a number of forces?
the single force that would have the same effect as all the other forces OR the vector sum of all the forces
Which two units can be used for momentum?
Ns OR kgms-1
Which of the following are scalars? Time, Momentum, Acceleration, Energy, Speed, Velocity, Displacement, Distance, Force
Scalars: Time, Energy, Speed, Distance
A ball is thrown upwards into the air and is allowed to fall and bounce. See graph.
Between which points on the graph is the ball travelling upwards?
A-B, E-F,
What is acceleration?
Rate of change of velocity OR change in velocity per second.
What is the difference between distance and displacement?
Distance is the length of the actual path travelled, Displacement is the straight line distance between where you started and where you finished, with a direction.
What is your weight in freefall?
0 Newtons
Explain how an object reaches it’s terminal velocity.
The weight of the object acts down towards the surface of the planet. As the object falls it accelerates, as it does this the air resistance up the way will increase as it falls faster. Eventually the weight = air resistance. This gives equal and opposite forces so the forces are balanced. This gives a constant velocity, terminal velocity.
How can an elastic collision be identified?
Calculate the total kinetic energy before the collision and the total energy after the collision.
If the total kinetic energy before the collision is equal to the total kinetic energy after the collision then it is an elastic collision.
What is gravitational field strength?
The force due to gravity per unit mass (kg)
What is Newtons First Law?
If balanced forces act on an object it will : Remain at rest or continue to travel at a constant velocity in a straight line
What would happen to your apparent weight if you were standing on a set of Newton scales and were in a lift that was accelerating downwards?
Your apparent weight would decrease, It would be equal to your weight minus the force to cause the acceleration downwards.