Physical science exam 2

Momentum (p)

the product of mass and velocity (p=mv)

Impulse

Change in momentum, force x time (FT= ^p)

Law of Conservation of Momentum

In a closed system with no external forces, total momentum remains constant

Elastic Collision

Objects bounce with no energy loss

Inelastic Collision

Objects may stick together, some energy is transformed (usually to heat or deformation)

Work (W)

Force x distance (W=Fd)

Energy

the ability to do work

Kinetic Energy (KE)

Energy of motion (KE= 1/2mv_²⁾

Potential Energy (PE)

Stored energy due to position (PE=mgh)

Mechanic Energy

Sum of kinetic energy (KE) and potential energy (PE)

Momentum

p=mv

Impulse

Ft= ^p

Work

W=Fd

Kinetic Energy

KE= ½ mv²

Potential Energy

PE=mgh

Mechanical Energy

ME= KE + PE

More time to stop

less force (air bags, crumple zones)

Elastic collisions

conserve both momentum and kinetic energy

In free fall

PE converts to KE

Gravity

attractive force between two masses

Universal Law of Gravitation

F=G * (m1 * m2) / r²

Free Fall

motion under gravity alone (acceleration = 9.8 m/s²⁾

Projectile Motion

curved path due to horizontal velocity + vertical free fall

Satellite

Object in orbit, falling around Earth

Orbital Speed

Speed at which satellite remains in stable circular orbit

Escape Velocity

minimum speed needed to escape Earth’s gravity

Gravity acts

equally on all masses in free fall

Horizontal and Vertical motions

are independent

Satellites are

in free fall but have enough horizontal speed to keep missing earth

Projectile paths

are parabolic

Double the distance between objects

gravitational force becomes 1/4

For satellites

speed must match the curve of Earth

Power

measure of how fast work is done. Power= work done/ time interval.