Question

A car is moving at 32 miles per hour. The kinetic energy of that car is 5 × 10^5 J.

How much energy does the same car have when it moves at 101 miles per hour?
Answer in units of J.

Answer 1

The car has approximately 1.42 × 10^6 J of energy when it moves at 101 miles per hour.

Step-by-step explanation:

First, we need to convert the initial velocity and kinetic energy to SI units:

Initial velocity: 32 miles per hour = 14.3 meters per second (rounded to 2 decimal places)

Kinetic energy: 5 × 10^5 J (given)

Next, we can use the formula for kinetic energy:

KE = (1/2)mv^2

where KE is the kinetic energy, m is the mass of the car, and v is the velocity of the car.

Solving for mass:

m = 2KE/v^2

Substituting the given values:

m = 2(5 × 10^5 J) / (14.3 m/s)^2 ≈ 1569.93 kg (rounded to 2 decimal places)

Now, we can use the same formula to calculate the kinetic energy of the car when it moves at 101 miles per hour (rounded to 2 decimal places):

KE = (1/2)mv^2 = (1/2)(1569.93 kg)(45.06 m/s)^2 ≈ 1.42 × 10^6 J

Therefore, the car has approximately 1.42 × 10^6 J of energy when it moves at 101 miles per hour.