Answer:
the engine cool to 40
at 14.07 minutes
Explanation:
Given information
T(5) = 70
= 100
C = 15
Newton's law of cooling :
T(t) = C + (
- C) 
where
T(t) = temperature at any given time
C = surrounding temperature
= initial temperature of heated object
k = cooling constant
to find the the time when the engine will be cooled down to 40
, we first need to find the cooling constant, k
when t = 5, T(5) = 70
so,
T(t) = C + (
- C) 
T(5) = 15 + (100 - 15) 
70 = 15 + (85) 
= (70 - 15) / 85
-5k = ln (55/85)
k = - ln (55/85) / 5
k = 0.087
thus, we have the eqaution
T(t) = 15 + (85) 
now we can determine the time when T(t) = 40
40 = 15 + (85) 
= (40-15)/85
-0.0087t = ln (25/85)
t = - ln (25/85)/0.087
t = 14.07 minutes
Answer:

Explanation:
Given that,
Mass of the car, 
Initial speed of the car, 
Final speed of the car, 
To find,
The maximum mass of grain that it can accept.
Solution,
We know that according to the law of conservation of momentum, the initial momentum is equal to the final momentum.




Therefore, the maximum mass of grain that it can accept is 2554.83 kg. Hence, this is the required solution.