Question

what is the definition of the word cause? *
a result or change that happens because of an event or process
speed in a particular direction
an event or process that leads to a result or change
to apply a push or pull to change the motion of an object
a push or a pull that can change the motion of an object
a push or pull changing motion between an object and the surface it is moving over
what is the definition of the word collision? *
the moment when two objects hit each other
velocity without a particular direction, only how fast an object is going
an event or process that leads to a result or change
to reach a conclusion using evidence and reasoning
a push or a pull that can change the motion of an object
the amount of matter that makes up an object

Explanation:

The word "cause" refers to an event or process that leads to a result or change. For "collision", it is defined as the moment when two objects hit each other. These are standard dictionary - like definitions.

Answer:

For "What is the definition of the word 'cause'?": an event or process that leads to a result or change
For "What is the definition of the word 'collision'?": the moment when two objects hit each other