Answer:
The units (km/h) tell you how to do this! 200km/3h = 66.66666666…. BUT technically you only have ONE significant digit: 3 so 66.666… rounded to ONE digit is 70km/h but that is probably not important in this intro class so V = 66.67 or 67 km/h
Answer:

Explanation:
Since fluid is pumping in and out at the same rate (5L/min), the total fluid volume in the tank stays constant at 350L. Only the amount of salt and its concentration changed overtime.
Let A(t) be the amount of salt (g) at time t and C(t) (g/L) be the concentration at time t
A(0) = 10 g
Brine with concentration of 1g/L is pouring in at the rate of 5L/min so the salt income rate is 5 g/min
The well-mixed solution is pouring out at the rate of 5L/min at concentration C(t) so the salt outcome rate is 5C g/min
But the concentration is total amount of salt over 350L constant volume
C = A / 350
Therefore our rate of change for salt A' is
A' = 5 - 5A/350 = 5 - A/70
This is a first-order linear ordinary differential equation and it has the form of y' = a + by. The solution of this is

So 
with A(0) = 10
c + 350 = 10
c = 10 - 350 = -340

The correct answer is A. 250N
Work is a product of force and distance.
That is, work done=force×distance
Therefore substituting for the values in the question:
500J=force×2m
force= 500Nm/2m=250N
another unit for work done is Nm as force as the SI unit of force is newtons and distance in meters
Answer:
Because plant means a life. Plants need foods and energy as same as human. So for a plant mostly need sun light and water.
They need water because water is collected through root of the plant and absorbed from the soil.
They need sun light because do the process of photosynthesis and plants need other gasses well as water and sun light for live and survive.
Explanation:
Hope i helped u...