Answer:
Net force on the block is 32 N.
Acceleration of the object is 6.4 m/s².
Explanation:
Let the acceleration of the object be
m/s².
Given:
Mass of the block is, 
Force of pull is, 
Frictional force on the block is, 
The free body diagram of the object is shown below.
From the figure, the net force in the forward direction is given as:

Now, from Newton's second law of motion, net force is equal to the product of mass and acceleration. So,

Therefore, the acceleration of the object in the forward direction is 6.4 m/s².
Answer:
An increase in pressure
Explanation:
The ideal gas law states that:

where
p is the gas pressure
V is the volume
n is the number of moles
R is the gas constant
T is the temperature of the gas
in the equation, n and R are constant. For a gas kept at constant volume, V is constant as well. Therefore, from the formula we see that if the temperature (T) is increase, the pressure (p) must increase as well.
Answer: 8400 J
Explanation:
The formula referenced in the question is:
Where:
is the thermal energy
is the mass of the water sample
is the specific heat capacity of water
is the variation in temperature
Solving:
This is the thermal energy released