The average speed of the car for the entire trip can be calculate by using:
where S is the total distance covered by the car, and t is the total time taken.
The total distance travelled by the car is:
while the total time taken is:
so, the average speed of the car is:
so, the correct answer is (3) 85 km/h.
Answer:
First law of thermodynamic state that energy is always conserved, in other word, energy cannot be created or destroyed.
This means that energy can only transfer from one source to another.
For example, the electricity we used to power our phone didn't come from nowhere.
We charge our phone using the energy from the electricity from the outlet.
The outlet gets its energy from the power plant, who generated that energy from burning coal.
The coal they burned got their energy while they were alive as plants.
The plants got their energy from the sun.
The sun got its energy from other cosmic stuff and so on...
My point is that the energy we use will always cycle around. It doesn't come from thin air and it doesn't disappear into thin air either. This help keeps things balance because if energy is created out of thin air then the earth might just blow up. If energy gets erased into thin air then there'll be nothing to fuel life.
It has to lose electrons to become positively charged, so it can attract a negatively charged oxygen ion.
For a pendulum with a massless rope 'L' meters long, swinging through
a small arc, the period of the swing is
2 π √(L/g) seconds .
and it doesn't depend on the mass of the thing on the end of the rope ...
that could be a pebble or a bus.
For the girl on the 2.5-m rope,
Period = (2 π) √(2.5 / 9.8) = 3.17 seconds
Frequency = 1 / period = about <em> 0.315 Hz .</em>
