reference frames
<img width="125" height="100" src="https://scienceres-edcp-educ.sites.olt.ubc.ca/files/2012/07/sec_phys_kinematics_1D_relativevelocity-125x100.jpg" class="attachment-post-thumbnail size-post-thumbnail wp-post-image" alt="" decoding="async" />
Relative Velocities
<img width="125" height="100" src="https://scienceres-edcp-educ.sites.olt.ubc.ca/files/2012/07/sec_phys_kinematics_2D_ballOnCart-125x100.jpg" class="attachment-post-thumbnail size-post-thumbnail wp-post-image" alt="" decoding="async" loading="lazy" />
Ball on a Moving Cart
<img width="125" height="100" src="https://scienceres-edcp-educ.sites.olt.ubc.ca/files/2012/07/sec_phys_kinematics_2D_cannonOnCart-125x100.jpg" class="attachment-post-thumbnail size-post-thumbnail wp-post-image" alt="" decoding="async" loading="lazy" />