Explanation:
A distance-versus-time graph gives the distance an object has traveled after a given time.
In a distance-versus-time graph the slope represents the the speed of the object because
is

And how steep the slope of the distance-versus-time graph is tells us how fast an object is moving; steeper the slope greater the speed. For example, a graph with slope 10 represents a greater speed than a graph with slope 2.
So the steepness of the slope of the distance-versus-time is the speed of the object, and greater the slope greater is the speed.
The second one is correct not sure about the first one sorry
Answer:
40 j, 80j.
Explanation:
P.E= mgh. G=10 m/s².
For 4m, P.E=1*10*4=40 joules.
For 8m, P.E=1*10*8=80 joules.
Answer:
A. They trap energy in the atmosphere.
Explanation:
Greenhouse gases are defined as gases that absorb and emit radiation within the infrared range. These gases allow the sun’s rays to pass through the ozone layer and warm the earth, but prevent this warmth from escaping atmosphere.
Greenhouse gases cause the greenhouse effect on planets. Examples of greenhouse gases in Earth's atmosphere are water vapor, carbon dioxide, methane, ozone etc.