Dynamics Flashcards
Formula for force
Force = mass x acceleration
State Newtons 1st law of motion
1) An object will stay at rest or continue to move with constant velocity unless there is a resultant force
State Newtons 2nd law of motion
2) Force = mass x acceleration
State Newtons 3rd law of motion
3) For every action there is an equal but opposite reaction
Formula for weight
Weight = mass x gravity
What is the gravity on earth?
10m/s^2
What is the gravity on the moon?
1.67m/s^2
What is air resistance?
The force that exists when an object moves in air.
It always opposes motion
What is normal reaction?
Exists between 2 objects which are in contact. It is opposite to weight. Normal reaction = weight
What is tension?
A force that exists in a rope or a spring
What is upthrust?
The upward force that water exerts on an object
What is inertia?
The reluctance of an object at rest to move or a moving object to stop
What is frictional force?
The force that exists between a moving object and its surface of contact. It opposes motion
What does frictional force produce?
Friction between 2 surfaces produces heat
How does friction help slow down a vehicle when brakes applied?
The brake pads are made to come in contact with a metal disc fixed to the wheels. Frictional force is produced between the brake pads and the metal disc that causes the vehicle to decelerate
How is a vehicle able to turn a corner?
Because there is frictional force acting on the surface of each tyre in contact with the road. If friction is low then the vehicle will skid.
What is centripetal force?
The force acting on an object undergoing circular motion, it is always directed towards the centre of the circular path
Where does the velocity of an object with centripetal force act?
Along the tangent of the circle where the object is found
An object moves at a constant speed along a circle. Explain why there is centripetal force although the speed is constant
Since the direction of velocity is changing, there is acceleration. Therefore there is a force
Examples of centripetal force (2)
1) The gravitational force acting on a satellite orbiting the earth
2) The electrostatic forces acting on electrons orbiting the nucleus
