# 1) car a has a mass of 1,000 kg and is traveling 60 km/hr. car b has a mass of 2,000 kg and is traveling 30 km/hr. compare

###### Question:

car a has a mass of 1,000 kg and is traveling 60 km/hr. car b has a mass of 2,000 kg and is traveling 30 km/hr. compare the kinetic energy of car a with that of car b?

a) equal

b) half as much

c) twice as much

d) four times as much

## Answers

C

Explanation:

Calculate EkA -kinetic energy of car A

m=1000kg

Va=16.66 m/s

EkA=m*Va²/2

Eka=(1000kg*277.556m²/s²)/2

Eka=138 777.8 J

Calculate kinetic energy of CarB:

m=2000 kg

Vb=8.33 m/s

Ekb=(m*Vb²)/2

Ekb=(2000kg*69.39m²/s²)/2

Ekb=69 388.9 J

compare Eka with EkB

Eka/Ekb=138 777.8 J/69 388.9

Eka/Ekb=2

c) Twice as much

Explanation:

As we know that kinetic energy is given by the formula

[tex]K = \frac{1}{2}mv^2[/tex]

here we know that

m = mass of the object

v = speed of the object

so here we will have kinetic energy of Car A

[tex]K = \frac{1}{2}(1000)(60^2)[/tex]

[tex]K_a = 1.8 \times 10^6[/tex]

now we have kinetic energy of B is given as

[tex]K_b = \frac{1}{2}(2000)(30^2)[/tex]

[tex]K_b = 0.9 \times 10^6[/tex]

So kinetic energy of Car A is double that of Kinetic energy of car B

twice as much

Explanation:

Using the formula for the amount of kinetic energy: K.E. = 1/2 m v2. You would find that car A has twice as much energy as car B.