Answer:
Explanation:
All the rest of the information is extraneous. The only 2 things you have to know are
d = 20 km
t = 8 minutes = 8/60 hours = 0.13333333
So the speed is s = d/t
s = 20/0.1333333 = 150 km/hour
Note: you have not specified what units the speed is. I suppose you could answer 20/8 = 2.5 km/min
Answer:

Explanation:
According to the free body diagram, in this case, we have:

Recall that the force of friction is given by:

Replacing and solving for the coefficient of kinetic friction:

We have an uniformly accelerated motion. Thus, the acceleration is defined as:

Finally, we calculate
:

My educated guess : 21.2 deg