A 1220 kg automobile travels at 75 m/s. what net work would be required to bring it to a stop

W = - 3431250 [N]

Explanation:

In order to solve this problem, we must use the theorem of work and energy conservation. This theorem tells us that the initial mechanical energy of a body plus the work done on this body must be equal to the final mechanical energy of the body. We must remember that the mechanical energy of a body is equal to the sum of kinetic energies plus potential energy plus elastic energy.

In this problem, we only have kinetic energy.

And we have:

m = mass = 1220 [kg]

v = velocity = 75 [m/s]

As the carriage stops the final kinetic energy is zero.

Now replacing:

Note: The negative force means that the force has to be carried out by the carriage. That is, no external force acts on the car to stop it.

wavelegth as in spectrum red oygbiv

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.