Which best describes how energy changes form in a car’s engine?

a) a single transformation occurs because the chemical energy of the fuel is changed to the mechanical energy of the car.
b) a single transformation occurs because the mechanical energy of the car originates from one spark.
c) multiple transformations occur because the chemical energy of the fuel is changed to several forms of energy.
d) multiple transformations occur because the chemical energy of the fuel must be replenished to keep the car running.

C) Multiple transformations occur because the chemical energy of the fuel is changed to several forms of energy.

Explanation:

Fuel has potential chemical energy. When fuel is introduced into the engine´s cylinder when you press the gas pedal, it is introduced with air. The mixture of fuel and air then ignites thanks to the spark plug in gasoline engines or thanks to high temperatures reached with high compression rates in diesel engines. When it ignites, you are converting the chemical energy into thermal energy. This thermal energy converts to mechanical energy to move the piston downwards and start rotating the crank shaft which then transmits power to the rest of the vehicle.

Energy changes from chemical to thermal to mechanical in a car´s engine. Being more strict, you could also include sound energy and light energy when the fuel mixture ignites but those are negliglible in calculations.

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west