It's 87.97 days of the orbital period going round the sun it's days of the shortest of all planets in the solar system.
This is Kinematics and the equations in your book.
A speed time graph would plot the speed of something against the teime it was at a speed.
If it were changing it speed constantly, that would be a straight line if acclerating. Total distrance would be the area under the graph.
Scientists can tell this by looking at seismic waves released by earthquakes. ( if you need me to elaborate more ask)
C. is the answer because acceleration is the change in velocity in time while velocity is speed with a direction
99.0km/h =27.5m/s (this is the initial speed)
The final speed is zero
The distance is 50.0m
Therefore you use the formula:
vfinal²=vinitial²+2ad
a=(vfinal²-vinitial²)/2d
= (0²-27.5²)/(2x50.0)
=-7.5625 or in correct sigdigs -7.56m/s²
Hope this helps!
