Answer: The slope of a line on a distance-time graph is- speed of the object.
The slope of a line on a graph refers to rate of change of variable that is presented on Y axis with respect to the variable that is presented on X axis.
For a distance time graph, distance is presented on Y axis and time on the X axis.
As we know that 
Therefore, the slope of a line on a distance-time graph represents speed of the object.
The force that acts on all objects, all the time on Earth is gravitational force.
The force that surface exert on an object perpendicularly is normal reaction.
<h3>What force acts on all objects, all the time on Earth?</h3>
- Force due to gravity is gravitational pull on objects due to its position on earth's surface.
The force due to gravity on object's is calculated by applying Newton's second law of motion as follows;
F = mg
where;
- m is the mass of the object
- g is acceleration due to gravity
The force that surface exert on an object perpendicularly is normal reaction.
Thus, the force that acts on all objects, all the time on Earth is gravitational force.
Learn more about force of gravity here: brainly.com/question/2537310
On the Newtonian theory of gravity, gravitation affects anything with mass. Assuming that none of the answer choices is the only thing that exists in the universe, all of the answer choices are subject to the law of universal gravitation (hence “universal”).
Satellites, water, frogs, and stars all have mass as they are all composed of matter. Thus, all four answer choices should be circled.
Answer:
the answers are the first and last option
2,3,5 are correct just took the test
