Consider the following scenario. A car for which friction is NOT negligible accelerates from rest down a hill, running out of gasoline after a short distance. The driver lets the car coast farther down the hill, then up and over a small crest. He then coasts down that hill into a gas station, where he brakes to a stop and fills the tank with gasoline. Identify the forms of energy the car has,

The answer is below

Explanation:

Gravitational Potential energy is the energy stored by an object as a result of its vertical position or height.

Kinetic energy is the energy an object possesses due to its motion.

The law of conservation of energy states that energy cannot be created or destroyed but can be transformed from one form to another.

As the car accelerates down the hill, there is a change in gravitational potential energy as a result of  decrease in vertical height. Some of the gravitational potential energy would be changed into work done by friction while the rest would cause an increase in kinetic energy due to the car acceleration. Lastly, when the brake is applied to stop the car, the car would lose its kinetic energy.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s