Question

Mrs. Waid drives her car up Route 8 at 80mph. If her car weighs 2500 lbs,

Answer 1

1.358 J is the kinetic energy of the car driven by Mrs. Waid.

Explanation:

Given data:

Velocity at which Mrs. Waid drives her car = 80 mph

In order to convert mph (meter per hour) into mps (meter per second),

         $\frac{80}{3600}=0.0222 \mathrm{m} / \mathrm{s}$

Car weighs 2500 lbs, means mass of the car, m = 2500 lbs

I kilo gram = 2.20462 pound

Therefore, 1 pound (lb)=  0.45359237 kilograms (kg).

To converting pounds into kilogram,

               $\frac{2500}{0.45359237}=5511.55 \mathrm{kg}$

As we know, the kinetic energy can be defined as directly proportionate to the object’s mass (m) and square of its velocity (v). The expression can be given as below,

               $\text { kinetic energy }(K . E)=\frac{1}{2} \times m \times v^{2}$

By substituting the given values, we get

              $\text { kinetic energy }(K . E)=\frac{1}{2} \times 5511.55 \times 0.0222^{2}$

              $\text { kinetic energy }(K . E)=\frac{1}{2} \times 5511.55 \times 0.00049$

              $kinetic energy (K . E)=1.358 joule$