Forces and motion (topic 2) Flashcards
What is Newton’s first law?
An object will continue moving in the same direction and speed until an external force acts upon it.
What is Newton’s second law?
A larger force is required to push a larger mass. The acceleration is dependent on the amount of force applied.
What is Newton’s third law?
Every action has an equal or opposite reaction.
What the formula for weight?
Weight(N) = mass(Kg) x acceleration due to gravity(9.81)
What is the value of acceleration due to gravity?
9.81
What is the formula for momentum?
Momentum(kgm/s) = mass (kg) x velocity (m/s)
What is the formula for force?
Force (N) = mass x acceleration fma
m/s
how to work out total distance?
X = v{2}-u{2}/2a
x = total distance
a = accelerationWhat is stopping distance equal to?
Stopping distance = thinking distance + braking distance
What do the safety features in modern cars aim to do?
Absorb energy(crumple zones, slightly stretchy seatbelts)
reduce injuries
reduce the momentum to zero slowly, to reduce injuries
What does the area under a speed time graph represent?
Distance
What is the equation for acceleration?
(V-u)/time
How do u calculate deceleration
Do the same as you would for acceleration and put a minus in front of the answer
Energy efficiency equation
Useful energy output/total energy input X 100
What is the name of he force which pushes back against the weight of an object
Lift
