1D Motion Concepts
Speed: 0 m/s |
Velocity: 0 m/s |
Acceleration: 0 m/s²
Concept Analysis
(a) With zero speed at an instant may have non-zero acceleration at that instant
True
Example: A ball thrown upward has zero speed at its peak but constant acceleration due to gravity (9.8 m/s² downward).
(b) With zero speed may have non-zero velocity
False
Speed is the magnitude of velocity. Zero speed means zero velocity (no direction and no magnitude).
(c) With constant speed must have zero acceleration
True
Constant speed in one dimension implies no acceleration. (Note: In 2D/3D, constant speed but changing direction would have acceleration.)
(d) With positive value of acceleration must be speeding up
False
Only true when positive acceleration aligns with velocity direction. If moving in negative direction, positive acceleration slows it down.



