| .. | . |
| what is meant by resultant vector | the combination of two or more vectors
(the result of adding vectors together) |
| what can any vector be resolved into | a horizontal and vertical component (perpendicular to each other)
These two components have the same effect as the initial vector when added together |
| how are the horizontal and vertical components of a vector expressed mathematically? | Fₕ=Fcos(θ)
Fᵥ=Fsin(θ) |
| what does Newtons first law state | objects at rest will stay at rest unless acted on by an unbalanced force
objects in motion will stay in motion with a constant velocity unless acted on by an unbalanced force |
| what changes can forces acting on an object cause? | an objects
shape
speed
direction |
| what is newtons second law? | when an unbalanced force acts on an object: the direction of the objects acceleration is the same as the direction of the unbalanced force the magnitude of the objects acceleration is directly proportional to the size of the unbalanced force the magnitude of the objects acceleration is inversely proportional to the objects mass |
| what is the equation for newtons second law? | f=ma
where f is UNBALANCED force in newtons
m is mass in kg
a is acceleration is ms-2 |
| what is this diagram called? | free body diagram |
| when dealing with weight of an object down a slope, what can weight be resolved into? | two independent components:
- one acting along/down the slope (parallel to the slope)
- one acting perpendicular to the slope |
| how would you mathematically express the component of weight acting parallel to the slope? | W=mgsinθ
(think of this as the vertical component) |
| how would you mathematically express the component of weight acting perpendicular to a slope? | W=mgcosθ
(think of this as the horizontal component) |
| what is the formula for work done when energy is transferred? | Ew=Fd
where Ew is work done in joules
F is Force in newtons
d is distance in metres |
| what is power | the rate at which energy is used or work is done
OR
energy transferred per unit time |
| what is the equation for power | E=Pt
where E is energy in joules
P is power in Watts
t is time in seconds |
| on a lift, what does the reading on the newton balance give? | the sum of all the forces acting upwards on the lift |
| why does the sound frequency of an object decrease as the object moves away | when the source moves away, the wave fronts are farther apart
when the source moves closer, the wave fronts become closer together |
| what is conserved in an elastic collision | total energy
total kinetic energy
total momentum |
