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#1. True or False: If an object is accelerating then it must be increasing it’s speed
Acceleration is a vector. This means it has both a magnitude and direction. Therefore, it is possible to accelerate whilst only changing direction. An example of this is an object in circular motion. As it is changing it’s direction it must be accelerating. This in turn means there must be a resultant force acting on the object. [See centripetal forces].
#2. What equation correctly describes Newton’s second law?
Better luck next time!
#3. True or False: Objects need forces to keep them in motion?
Forces cause the motion of an object to CHANGE i.e. accelerate. If there is a resultant force on an object then that object will either increase it’s velocity, decrease it’s velocity or change it’s direction (changing the direction of the object’s velocity but not it’s magnitude).
An object in motion does not need a force to keep it in motion. In fact, as long as the resultant force on an object remains zero, an object will continue to travel at it’s current velocity forever! An example of this can be seen by astronauts in the International Space Station. If they throw an object it will continue travelling at a constant velocity until it collides with something and therefore experience a force changing it’s motion!