Recall that

The car starts from rest, so
, and we get

Answer:
When the temperature of the coffee is 50 °C, the time will be 20.68 mins
Explanation:
Given;
The initial temperature of the coffee T₀ = 95 °C
The temperature of the room = 21°C
Let T be the temperature at time of cooling t in mins
According to Newton's law of cooling;

When the temperature is 50 °C, the time t in min is calculated as;

Therefore, when the temperature of the coffee is 50 °C, the time will be 20.68 mins
Answer: 
Explanation:
If we have an initial amount of a radioactive material or substance, which is
, and we also are told this amount decays
each year, this means each year
of the substance remains:

<u />
<u>To understand it better:</u>
Year 1: 
Year 2: 
Year 3: 
and so on until year
:
Year t: 
Therefore, the function tha best describes this radiation decay situation is:

Given
The projectile is in air for a time of t=8 sec
To find
The time it takes to reach the highest point
Explanation
A projectile moves up to the highest point and then again moves down following a parabolic path.
So it will reach the highest point at a time half the time it requires to follow teh parabolic path.
The time taken to reach the highest point is 4 sec
Conclusion
The time taken is 4 sec.
(ff) fortissimo means very loud