Answer:
magnitude of A − B = 15.81 km
Explanation:
Vector A points in the negative y-direction and has a magnitude of 5 km. Vector B points in the positive x-direction and has a magnitude of 15 km.
According to Cartesian coordinate system, the resultant will start either from tail of A and ends at head of B and vice-versa.
A(0,-5)
B(15,0)
A - B = (-15 i - 5 j )
Magnitude of the vector is given by
|A - B| = 
|A - B| = 
|A - B| = 15.81 km
2.c
3.b
1.a
......................................................................................................................................................
Distance, since distance represents how far something has travelled, which would be in our case 2.5m.
Answer:

Explanation:
mass of the bicycle + cyclist = 50 kg
constant speed = 6 km/h
a cyclist coasting down a 5.0° incline
the downward velocity is constant, so net acceleration must be zero
the air drag must be equal to gravitational force downward along the ramp
now for upward motion





I would look this one up on Google