FIRST YEAR PHYSICS FIRST PHYS141
LECTURER: Dr. Carey Freeth
Rm 4.110 Ph. 02 42214798 Email: [email protected]
Physics The Science of Measurement and Theory
Physics attempts to describe the fundamental nature of the universe and gives us an understan
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Useful Information
Acceleration of gravity at earths surface g = 9.81 m/s2
1
v = v0+ at
x = x0 + v0t + 1/2 at2
2
v =
v 20
+ 2as.
x = x0 + vavt = x0 + /2(v0 + v)t
vpB = vpA + vAB
C = A + B = (Ax i + Ay j + Az k) + (Bx i + By j + Bz k)
(ax)drag
Centre of Percussion Where would we apply a force so there is no reaction force at the pivot? x We have pure rotation about the pivot point so = acm/(L/2) if the rod is of length L.
Fp
F0
Similar to above then F = macm and p = Ip.
Except we have taken the
Hypothetical You applied for a summer job in Scotland - Carey gives reference Scotland (Lockerbie) Pan Am Flight 103 rst project.
Know exact location and velocity of plane at time of explosion.
Etc etc.
Special Case: Where Net External Forces are Zero In
FIRST YEAR PHYSICS FIRST PHYS141
LECTURER: Dr. Carey Freeth
Rm 4.110 Ph. 02 42214798 Email: [email protected]
We will now develop some techniques for solving problems where the forces acting on a body are not all constant. Consider rst, a simple sit
The tangential component of the contact force exerted by one body on another is called the frictional force. For example if we sit a block on an incline it will not necessarily side down.
This is because the incline exerts a force, the frictional force, e
FIRST YEAR PHYSICS FIRST PHYS141
LECTURER: Dr. Carey Freeth
Rm 4.110 Ph. 02 42214798 Email: [email protected]
FORCES are what move and accelerate objects. Types of forces a) Contact Forces (require contact) - Pushing - Pulling b) Field Forces (do no
FIRST YEAR PHYSICS FIRST PHYS141
LECTURER: Dr. Carey Freeth
Rm 4.110 Ph. 02 42214798 Email: [email protected]
The description of motion is now extended to the more general cases of motion in two and three dimensions by using vectors and the one dime
Use the procedure of integration. If we know the acceleration, then we can nd v(t) and x(t) as follows: !v dv so that dv = adt a = lim = !t - > 0 ! t dt and if in time t, the objects velocity has gone from v0 to v;
!v 0 dv = !0 adt = a !0 dt,
Hence v - v0
THERMODYNAMICS
Thermodynamics : study of heat
temperature
heat exchange
heat and work.
Applications:
Engine efficiency- reduce "cost" of work (money &
environment).
Energy balance in animals food input, work and heat output
must balance to maintain tem