Question

1. State the formula for Kinetic energy (Ek) of an object and label all three variables in this equation (write down what each variable represents and the unit of the variable). In other words, explain what is what in the formula and the units used.

2. Can a slow moving object have a large amount of kinetic energy? Defend your answer with a sound argument.

3. Calculate Ek of an 800 kg car traveling at 72 km/h. Express your answer in Joules! (if you want the answer to come out in Joules you will need to change the speed from km/h to m/s!) Show your calculation!

Answer 1

1.

Kinetic energy of an object is given by

Where M=Mass of the moving object

V=Speed of the object

The Units of Kinetic energy are Joules

2.

Yes ,if the slow moving object has a larger mass then the amount of kinetic energy is very large.for examle consider

Let speed of the object be V=2 m/s and mass of the object be m=100000 kg .Then the kinetic energy is

3.

Given speed of the car is

V=72 *1000/3600 =20 m/s

Therefore kinetic energy of car is