MOTION d s t Average speed = change in distance change in time S = Δd / Δt Velocity includes speed and direction!! Speed constant…velocity changing…acceleration changing

ΔvΔv a Δt Acceleration = final velocity - initial velocity final time - initial time a = Δv/Δt Newton’s 1 st Law of Motion An object at rest remains at rest unless acted upon by an unbalanced net force or An object moving at a constant velocity continues to move at that velocity unless acted upon by an unbalanced net force

Forces 4 Basic Forces: gravity, strong nuclear force, weak nuclear force, electromagnetic force Newton’s 2 nd Law of Motion An object’s acceleration is in the same direction as the net force acting upon it Acceleration(m/s 2 ) = net force(N)/mass(kg) a = F net / m

Law of Universal Gravitation Find the force of gravity between 2 objects, if masses and distance between them are known Gravitational = (constant) x (mass1)x(mass2) force (distance) 2 F = G m 1 m 2 d 2 Note force changes as mass and distance changes!

Force of Earth’s Gravity and an object’s Weight on Earth Force of = mass(kg) x acceleration of gravity(N) gravity (9.8m/s 2 ) F = mg Weight on = mass(kg) x acceleration of Earth gravity(9.8m/s 2 ) W = mg An Object’s Weight on Earth is the Force of Gravity acting upon that object!!

Newton’s 3 rd Law of Motion When one object exerts a force on a second object, that second object exerts a force that is equal in strength, and opposite in direction or For every action force, there is an equal and opposite reaction force F 1 Dir 1 F 2 Dir 2 The skater throws the ball with force F1 in the direction Dir 1; The ball exerts a force F2 on the skater, who moves in the opposite direction Dir 2

Law of Conservation of Momentum If a group of objects exerts forces only on each other, the total momentum is conserved M 3 M 1 v 1 M 1 v 1 ’ M 2 v3v3 v2v2 M 1 V 1 = M 1 V 1 ’ + M 2 V 2 + M 3 V 3

Work W(Nm) = F(N) x d(m) d1d1 d2d2 F1F1 F2F2 How do the distances d 1 and d 2 compare? F 1 and F 2 ? How does the work to move the object from floor to shelf by direct lifting compare to that by using the ramp? Is there any advantage to using the ramp?

Mechanical Advantage Mechanical Advantage = Force (out) / Force (in) MA = Output Force = Lift Force (no ramp) Input Force Force with ramp

POWER Power = rate of Energy Use = rate of Work completion Power (Watts) = Energy (Joules) Time (s) P = E/t = W/t