Biology Forums - Study Force

A accelerates from rest to 30mph. After a while the car is travelling at a 50mph. If the car is acclereated at the same rate from 50mph to 60mph, then which takes more energy?

a) 0-30 mph

b) 50-60 mph

c) both the same

d) cannot tell from the information.

The question is about the kinetic energy of a car, which is the energy it has due to its motion. The formula for kinetic energy is:
K.E.=21​mv2

where m is the mass of the car, and v is the velocity (or speed) of the car.

To answer the question, you need to compare the change in kinetic energy when the car accelerates from 0 to 30 mph, and when it accelerates from 50 to 60 mph. You can assume that the mass of the car is constant, so you only need to focus on the velocity.
You also need to convert the velocities from miles per hour (mph) to meters per second (m/s), which is the standard unit for velocity in physics. You can use this conversion factor:

1 mph=0.44704 m/s
So, for example, 30 mph is equivalent to:
30×0.44704=13.4112 m/s

You can do the same for the other velocities.

Then, you can plug in the values into the kinetic energy formula and calculate the difference between the initial and final kinetic energies for each case.