Answer:
The first part can be solved via conservation of energy.

For the second part,
the free body diagram of the car should be as follows:
- weight in the downwards direction
- normal force of the track to the car in the downwards direction
The total force should be equal to the centripetal force by Newton's Second Law.

where
because we are looking for the case where the car loses contact.

Now we know the minimum velocity that the car should have. Using the energy conservation found in the first part, we can calculate the minimum height.

Explanation:
The point that might confuse you in this question is the direction of the normal force at the top of the loop.
We usually use the normal force opposite to the weight. However, normal force is the force that the road exerts on us. Imagine that the car goes through the loop very very fast. Its tires will feel a great amount of normal force, if its velocity is quite high. By the same logic, if its velocity is too low, it might not feel a normal force at all, which means losing contact with the track.
The power require to keep the car traveling is 6,666 W.
The power of the engine at the given efficiency is 3,999.6 W.
<h3>What is Instantaneous power?</h3>
This the product of force and velocity of the given object.
The power require to keep the car traveling is calculated as follows;
P = Fv

The power of the engine at the given efficiency is calculated as follows;

Learn more about efficiency here: brainly.com/question/15418098
Magnetic field is the magnetic effect of electric currents and magnetic materials. The magnetic field at any given point specified by both direction and a magnitude. So uniform magnetic field has equal amount of force or magnetic force in both side of the object while the non uniform magnetic field has one of the object exert more than the other
Answer:
Density of unknown liquid is 
Explanation:
When rock is suspended in air then the weight of the rock is counter balanced by the tension force in the string
So here we have

now when the rock is immersed in water then the tension in the string is and buoyancy force due to water is counter balanced by the weight of the object
so here we have



now we have


now when the rock is immersed into other liquid then we have



now we have

