Answer A an Open Universe
The future of universe is predicted from space time curve. There are many possibilities solutions or outcomes which on plotting are classified as open, close, flat and curved. Open Universe is when universe is expanding and it will continue to expand forever. This is proved experimentally as well that universe is expanding using red and blue shift observations from various aspects.
Average speed=total distance traveled/time. Total distance=the sum of the two short distances=79*2+77*3=389 km. Total time used to travel is 2+3=5 hr. Average speed is 389/5=77.8 km/hr.
Answer:
75 N
Explanation:
In this problem, the position of the crate at time t is given by
The velocity of the crate vs time is given by the derivative of the position, so it is:
Similarly, the acceleration of the crate vs time is given by the derivative of the velocity, so it is:
[m/s^2]
According to Newton's second law of motion, the force acting on the crate is equal to the product between mass and acceleration, so:
where
m = 5.00 kg is the mass of the crate
At t = 4.10 s, the acceleration of the crate is
And therefore, the force on the crate is:
Answer:
Cp = 4756 [J/kg*°C]
Explanation:
In order to calculate the specific heat of water, we must use the equation of energy for heat or heat transfer equation.
Q = m*Cp*(T_f - T_i)/t
where:
Q = heat transfer = 2.6 [kW] = 2600[W]
m = mass of the water = 0.8 [kg]
Cp = specific heat of water [J/kg*°C]
T_f = final temperature of the water = 100 [°C]
T_i = initial temperature of the water = 18 [°C]
t = time = 120 [s]
Now clearing the Cp, we have:
Cp = Q*t/(m*(T_f - T_i))
Now replacing
Cp = (2600*120)/(0.8*(100-18))
Cp = 4756 [J/kg*°C]
Answer:
50,000 V/m
Explanation:
The electric field between two charged metal plates is uniform.
The relationship between potential difference and electric field strength for a uniform field is given by the equation
where
is the potential difference
E is the magnitude of the electric field
d is the distance between the plates
In this problem, we have:
is the potential difference between the plates
d = 15 mm = 0.015 m is the distance between the plates
Therefore, rearranging the equation we find the strength of the electric field:
