Forces and motion Flashcards
1
Q
formula for weight
A
weight = mass X g
2
Q
What is vector
A
A quantity with direction and magnitude
3
Q
What is scalar
A
A quantity with only magnitude
4
Q
What are the different SUVAT equations
A
v= u+at
V^2= u^2 + 2as
S=ut+(at^2)/2
S = t (v+u)/2
S = vt−(at^2)/2
5
Q
What does SUVAT stand for
A
S - Displacement
U - Initial velocity
V - Velocity
A - Acceleration
T - Time
6
Q
What are:
Newton’s 3 laws
A
if an object is moving at constant velocity, the forces acting on it must be =
F = MA
If Body a exerts a force on body b, body b exerts exactly the same force in the opposite dirextion with the same magnitude
7
Q
What are the changes in:
Force experienced by a parachutist
A
- Skydiver jumps out of the plane and is accelerating downwards at 10ms^-2. Resultant force is downwards because only weight is acting
- A few moments later the skydiver has a velocity less than max going downwards and accelerating at <10ms^-2 as air resistance kicks in. Resultant force is downwards
- Terminal velocity is reached as drag is equal to weight and there is no acceleration. Velocity is going downwards at the maximum speed. Resultant force is 0.
- The parachute is pulled and the AR has a very large arrow upwards, but the velocity has not changed. Resultant force is upwards.
- A few moments later the acceleration is still upwards, but less, and the velocity is downwards and less than max. Resultant force is upwards, but less than a few moments before.
- A new terminal velocity is reached as AR = W. The acceleration is 0 and the new terminal velocity is much smaller than the other one. The velocity is still going downwards. Terminal velocity is 0.
8
Q
A