Question

1. An automobile traveling at 25 km/hour has kinetic energy equal to 1x 10^4J.

a What is the mass of the car?

b. If the velocity of the car is increased to 45 km/hour, what is its kinetic energy?

c. If the velocity is increased to 80 km/hour, what is its kinetic energy?
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Answer 1

Step-by-step explanation:

It is given that,

Speed of an automobile is 25 km/h or 6.95 m/s

Kinetic energy of the automobile is
`10^4\ J`

(a) Kinetic energy of automobile s given by :

`K=(1)/(2)mv^2\\\\m=(2K)/(v^2)\\\\m=(2* 10^4)/((6.95)^2)\\\\m=414\ kg`

(b) If the velocity of the car is increased to 45 km/hour or 12.5 m/s, new kinetic energy becomes :

`K=(1)/(2)* 414* (12.5)^2\\\\K=32343.75\ J`

(c) If the velocity is increased to 80 km/hour, 22.23 m/s, So

`K=(1)/(2)* 414* (22.23)^2\\\\K=102293.79\ J`

Hence, this is the required solution.