Section 11: Forces Part 2 Flashcards
What formula links velocity, time and acceleration?
Acceleration = change in velocity/time taken a = Δv/t
(HT) What are the characteristics of speed and velocity in a circular orbit?
Constant speed, changing velocity
State Newton’s first law of motion
If there is no resultant force on an object, it ill continue with a constant velocity if moving or remain at rest if stationary
What does Newton’s first law tell us about objects moving with uniform velocity?
The resultant force on the object must be zero
What does Newton’s first law tell us about objects moving with changing speed or direction?
There must be a resultant force on the object
State Newton’s second law of motion
Force = mass x acceleration F = ma
(HT) What is inertial mass?
A measure of how difficult it is to change the velocity of an object: the ratio of force over acceleration
State Newton’s third law of motion
Every force is paired with an equal and opposite reaction force
(HT) What is momentum?
The quantity of motion of a moving object: the product of mass and velocity
(HT) What is the formula for momentum?
Momentum = mass x velocity ρ = mv
(HT) What happens to momentum in collisions?
It is conserved: total momentum before the collision = total momentum after the collision
What dangers are caused by large decelerations in events such as car crashes?
Large forces on passenger can lead to serious injury
