Answer:
27.5 m/s
Explanation:
applying motion equations we can find the answer,
v = u + a*t
Let assume ,
u = starting speed(velocity)
v = Final speed (velocity)
t = time taken for the motion
a = acceleration
by the time of reaching the highest point subjected to the gravity , the speed should be equal to zero (only a vertical speed component is there)
for the complete motion it takes 5.5 s. that means to reach the highest point it will take 5.5/2 =2.75 seconds
we consider the motion upwards , in this case the gravitational acceleration should be negative in upwards (assume g=10 m/s2)
that is,
v = 0 , a = -10 , t =2.75
v = u + at
0 = u -10*2.75
u = 27.5
Energy Conservation Theory,
The principle of energy conservation states that energy is neither created nor destroyed. It may change from one sort to another. Just like the mass conservation rule, the legitimacy of the preservation of energy depends on experimental perceptions; hence, it is an experimental law. The law of preservation of energy, too known as the primary law of thermodynamics
To learn more about Energy Conservation Theory, visit;
#SPJ4
Answer : The correct option is, (B) -5448 kJ/mol
Explanation :
First we have to calculate the heat required by water.
where,
q = heat required by water = ?
m = mass of water = 250 g
c = specific heat capacity of water =
= initial temperature of water = 293.0 K
= final temperature of water = 371.2 K
Now put all the given values in the above formula, we get:
Now we have to calculate the enthalpy of combustion of octane.
where,
= enthalpy of combustion of octane = ?
q = heat released = -81719 J
n = moles of octane = 0.015 moles
Now put all the given values in the above formula, we get:
Therefore, the enthalpy of combustion of octane is -5448 kJ/mol.
A) Time needed: 6.24 s
B) Time needed: 2.86 s
Explanation:
A)
In this part, we are told that the power if the engine is constant. The power of the engine is given by
where
W is the work done
t is the time
This means that the power of the engine is proportional to the work done, and therefore, to the kinetic energy of the car:
where m is the mass of the car and v its velocity.
SInce power is constant, we can write:
where:
is the time the car needs to accelerates to
is the time the car needs to accelerate to
Therefore, solving for ,
B)
First of all, we have to calculate the acceleration of the car. We can do it using the following equation:
where:
u = 0 is the initial velocity
is the final velocity
t = 1.40 s is the time elapsed
Substituting, we find the acceleration:
In this part, we are told that the force exerted by the engine is constant: according to Newton's second law, acceleration is proportional to the force,
This means that the acceleration is also constant.
Now we want to find how long the car takes to accelerate to a final velocity of
From an initial velocity of
u = 0
Using again the same suvat equation, and using the acceleration we found previously, we find:
Learn more about accelerated motion:
About power:
#LearnwithBrainly