P10 Flashcards
WHAT DOES NEWTONS SECOND LAW OF MOTION STATE?
That if a non zero resultant force acts on an object, it accelerates
IF THERE IS NO ACCELERATION…
RESULTANT FORCE IS EQUAL TO 0
WHAT EQUATION REPRESENTS NEWTONS SECOND LAW?
Force(N)=mass(kg) x acceleration (m/s2)
WHAT DOES THIS EQUATION SHOW?
Acceleration is directly proportional to force ( big force big acceleration ) and inversely proportional to mass ( big mass small acceleration)
WHAT IS THE EQUATION FOR WEIGHT?
Weight (N) = mass (kg) x 9.8 (N/kg)
WHAT IS TERMINAL VELOCITY?
When velocity reaches a point where it remains constant and no longer accelerates or deaccelerates
EXPLAIN IN 3 STEPS WHAT HAPPENS TO S KYDIVER WHEN THEY JUMP OUT A PLANE?
1.When a skydiver jumps out a plane there force of weight immediately acts downwards causing them to fall
2. As they fall air resistance will begin to act upwards, cancelling out the downwards fall so skydiver slightly slow downs
3. as more and more air particles collide with your body air resistance eventually becomes equal to weight, the resultant force is 0 meaning terminal velocity is reached
A GREATER BRAKING FORCE IS NEEDED WHEN
vehicle is moving quicker so bigger deacceleration required for it to stop
WHAT IS SUM FOR STOPPING DISTANCE?
stopping distance= thinking distance= braking distance
WHAT IS THINKING DISTANCE?
the distance travelled during drivers reaction time
WHAT IS BRAKING DISTANCE?
the distance travelled under braking force
WHAT ASPECTS CAN EFFECT THINKING DISTANCE?
reaction time
-tired
-under influence of drugs and alcohol
WHAT ASPECTS EFFECT BRAKING DISTANCE?
-road conditions
- weather
-quality of brakes
WHAT IS EQUATION FOR DEACCELERATION?
v2= u2-2as
WHAT IS A MOMENTUM?
a property all moving objects have
WHAT IS THE EQUATION FOR MOMENTUM?
momentum(kg m/s) = mass (kg) x velocity (m/s)
WHAT IS CONSERVATION OF MOMENTUM?
the idea of momentum being conserved is with in a closed system total momentum before collision= total momentum after collision
WHEN TWO VEHICLES COLLIDE THEY…
-EXERT EQUAL AND OPPOSITE FORCES
-AND CHANGE OF MOEMNTUM IS EQUAL AS IT IS CONSERVED
EQUATION FOR IMPACT FORCE IS?
Force (N) =
mass (kg) x change in velocity (m/s)
/time (s)
FROM THE EQUATION WE CAN TELL?
greater mass = greater force
greater change in velocity+ greater force
shorter time= greater force
WHY DO CARS HAVE SAFETY FEATURES?
To reduce impact force and therefore force on person is less
WHAT DOES AN AIRBAG DO?
Increases impact time on drivers head and neck so force is decreased
WHAT DOES A SEATBELT DO?
stretches to prevent person being flung out of car, due to the stretch more time is taken for the body to change momentum so less impact force on body
