Answer: 
Explanation:
The acceleration of an object can be calculated by using Newton's second law:
where
F is the net force applied on the object
m is the mass of the object
a is its acceleration
In this problem, we have F=125 N and m=25.0 kg, so we can rearrange the equation to calculate the acceleration:
The number of protons an element has is its atomic number so the atomic number would be 29
Given: Heat Qout means useful work = 2800 J
Heat Qin = 8900 J
Required; Efficiency = ?
Formula: Efficiency = Qout/Qin = x 100%
= 2800 J/8900 J = 0.3146 X 100 %
Efficiency = 31.46%
Answer: 
Explanation:
We are given the following formula:
(1)
Where:
is the amount of heat
is the mass of water
is the specific heat of water
is the variation in temperature, which in this case is 
Rewriting equation (1) with the known values at the right side, we will prove the result is 
:
(2)
This is the result
Acceleration is maximum. <span>Velocity is decreasing. Acceleration is increasing</span>
