Answer:
D. Wind turbines take up a lot of space.
Explanation:
In wind turbines the kinetic energy received by the air molecules is converted into electrical energy by the use of turbines
So here in order to get more kinetic energy from air we need more crossectional area of the wind mill to interact with the air
So here we need the large size of turbines
so this is the main disadvantage of the wind turbines because it needs large area to install the whole setup also the efficiency of this turbine is small so it needs large number of wind mills to setup good output power
so correct answer will be
D. Wind turbines take up a lot of space.
Answer: option 1. thermal expansion and contraction.
The thermostat uses the thermal expansion and contraction of metals: when the metal expands it acts as a switch, a coiled ribbon expands and the electric circuit is off, then the current stops. When the temperatures decrease, the coiled ribbon contracts and the circuit is on, then the current starts to flow and the resistance starts to radiate heat.
First we need to know the specific heat capacity of water. You can look it up online because it is uniform. The specific heat capacity of water is 4184 kg^-1 °C^-1.
To calculate the energy required to heat a specific thing up, we can use the formula
E = mc△T
Where E is the total energy required, m as mass, c as specific heat capacity and △T
Substitute the numbers in
E = 1 x 4184 x 5
E = 20920J
Therefore the answer is 20920 joules
Jennifer is able to drag her brother out of the zoo due to an applied net force of 15 N.
<h3>What is force?</h3>
Force refers to any agent which tends to cause a change in the motion or state of an object.
Forces are of two types;
- contact forces, and
- Non-contact forces
The net force is the difference between two forces which causes a change in the motion of an object.
The net force that Jennifer applies = 35 N - 20 N = 15 N
Therefore, Jennifer is able to drag her brother out of the zoo due to an applied net force of 15 N.
Learn more about Net force at: brainly.com/question/141439
#SPJ1
Answer:
Explanation:
Given data:
Momentum of moving model train,
Mass of the stationary model train,
Initial speed of the stationary model train,
Assume there is no external force is acting on the given train system.
In this case, the total linear momentum of the trains would be conserved.
Let the final linear momentum of the trains be
Thus,