Answer:
t ’= 
, v_r = 1 m/s t ’= 547.19 s
Explanation:
This is a relative velocity exercise in a dimesion, since the river and the boat are going in the same direction.
By the time the boat goes up the river
v_b - v_r = d / t
By the time the boat goes down the river
v_b + v_r = d '/ t'
let's subtract the equations
2 v_r = d ’/ t’ - d / t
d ’/ t’ = 2v_r + d / t
In the exercise they tell us
d = 1.22 +1.45 = 2.67 km= 2.67 10³ m
d ’= 1.45 km= 1.45 1.³ m
at time t = 69.1 min (60 s / 1min) = 4146 s
the speed of river is v_r
t ’= 
t ’=
In order to complete the calculation, we must assume a river speed
v_r = 1 m / s
let's calculate
t ’= 
t ’= 547.19 s
Answer:
The mass of the cube is 420.8 kg.
Explanation:
Given that,
Length of edge = 38.9 cm
Density 
We need to calculate the volume of cube
Using formula of volume
We need to calculate the mass of the cube
Using formula of density
Hence, The mass of the cube is 420.8 kg.
Answer:
1.) Employee Driven Machines
2.) Self Driven Machines
Explanation:
A machine is a mechanical device that utilizes the application of forces to carry out an operation. It's operation can be "employee driven" (i.e it is operated by a person) or "self driven" (i.e it is operated by itself).
Answer:
C. The structure has numerous features indicating alignments with movements of the Sun and cultural heritage claimed that the rulers were descendants of the Sun.
Explanation:
If you know the formula for horizontal range, then finding the solution is immediate:
