P10 Force and motion Flashcards
What is the equation for resultant force?
Resultant (N) = mass (kg) x acceleration (m/s2)
What is the relationship between the resultant force and acceleration of an object?
The greater the resultant force of an object, the greater the object acceleration
What is the relationship between the mass and acceleration of an object?
The greater the mass of an object, the smaller its acceleration
What does Newtons second law of motion state?
The acceleration of an object is:
1. proportional to the resultant force on the object
2. inversely proportional to the mass of the object
What is meant by the inertia of an object?
Its tendency to stay at rest or in uniform motion
What is the mass of an object?
The quantity of matter in it
What is the weight of an object?
The force of gravity that acts on it
What is the equation for weight?
Weight (N) = mass (kg) x acceleration due to gravity (m/s2)
What is the terminal velocity of an object?
The velocity it eventually reaches when it is falling and the weight of the object is equal to the frictional force on it
What is the resultant force of an object if it is moving at terminal velocity?
Zero
What opposes the driving force of a vehicle?
Friction and air resistance
What is the stopping distance of a vehicle?
Thinking distance + braking distance
What is thinking distance?
The distance a vehicle travels during the drivers reaction time
What is braking distance?
The distance a vehicle travels under the braking force
How do you calculate the deceleration of a vehicle?
Final speed^2 (m/s) = initial speed^2 (m/s) + 2 x acceleration (m/s2) x distance (m)
What is the equation for momentum?
Momentum (kg m/s) = mass (kg) x velocity (m/s)
What is the relationship with mass and velocity with momentum?
The greater the mass and the greater the velocity of an object, the greater its momentum
What is the law of conservation of momentum?
Total momentum before an event = total momentum after an event
What is a closed system?
Where no energy is added and none can escape
How do you calculate the impact force that an object exerts in a collision?
Mass (kg) x change in velocity (m/s) / time taken for collision to occur (s)
What is the relationship between mass and impact force?
The greater the mass, the greater the impact force
What is the relationship between the time taken for the collision and impact force?
The shorter the time taken for the collision, the lesser the impact force
What is the relationship between the change in velocity and impact force?
The greater the change in velocity, the greater the impact force
What is the equation for impact force?
Impact force = change in momentum/time
How do cycle helmets reduce impact forces?
By increasing the impact time
