y2 ch5/7 Flashcards
1
Q
how to find magnitude of vector (angles)
A
using the cosine rule
2
Q
how to find angle theta
A
sine rule
3
Q
what does the maximum friction depend on
A
- how rough the surface is
- how hard the block is pressing against the surface ( how large the reaction force is)
4
Q
equation for the maximum friction between two surfaces
A
Frmax = mew x R :
- where mew is the coefficient and R is the normal reaction between two surfaces
5
Q
the coefficient of friction…
A
is always greater than 0 and usually less than 1.5
- specific for the particle and the surface it’s on
eg:
a box on sandpaper would have a high coefficient of friction
a box on ice would have a low coefficient of friction
a box on a smooth surface would have a coefficient of 0 as theres no friction
6
Q
friction
A
acts opposite to its direction of motion
can be less than its maximum value if the particle is not moving
