Answer:
Yeah
Explanation:
I mean, how about gravity for example! When you draw a free-body diagram, you will almost always have to include gravity. How about normal force, or static friction? There are defintely forces at hand.
Answer:2.45 m/s
Explanation:
Given
Launch velocity
launch angle
as the vertical velocity first decreasing to zero and then increases to original value so its avg is zero .



thus 

A. Formula: F=ma or F/m=a
10,000N/1,267kg≈7.9m/
B. Formula: a=
and s=d/t
speed= 394.6/15
s=26.3m/s
a=
a=1.75m/
C. 7.9-1.75=difference of 6.15m/
D. The force that most likely caused this difference is friction forces